Raised frame bulk acoustic wave devices

ABSTRACT

Aspects of this disclosure relate to bulk acoustic wave devices that have a raised frame structure, and filters that utilize the bulk acoustic wave devices. The raised frame structure can include a first raised frame layer that has a relatively low acoustic impedance. The raised frame structure can include a second raised frame layer that has a relatively high acoustic impedance. The first raised frame layer can extend inward further than the second raised frame layer. A width of the first raised frame layer that overlaps the first and second electrodes is between about 1.5 times to about 4 times larger than the combined thickness of the first electrode, the piezoelectric layer, and the second electrode.

CROSS REFERENCE TO PRIORITY APPLICATIONS

This application claims the benefit of priority of U.S. ProvisionalPatent Application No. 63/166,100, filed Mar. 25, 2021 and titled“RAISED FRAME BULK ACOUSTIC WAVE DEVICES,” and also claims the benefitof priority of U.S. Provisional Patent Application No. 63/166,126, filedMar. 25, 2021 and titled “FILTERS WITH RAISED FRAME BULK ACOUSTIC WAVEDEVICES,” the entire contents of each of which are hereby incorporatedby reference herein.

BACKGROUND Field of the Disclosure

Some embodiments disclosed herein relate to acoustic wave devices, suchas bulk acoustic wave devices, and to filters that include bulk acousticwave devices.

Description of the Related Art

Acoustic wave filters can be implemented in radio frequency electronicsystems. For example, filters in a radio frequency front end of a mobilephone can include one or more acoustic wave filters. A plurality ofacoustic wave filters can be arranged as a multiplexer. For instance,two acoustic wave filters can be arranged as a duplexer.

An acoustic wave filter can include a plurality of resonators arrangedto filter a radio frequency signal. Example acoustic wave filtersinclude surface acoustic wave (SAW) filters and bulk acoustic wave (BAW)filters. BAW filters can include BAW resonators. In BAW resonators,acoustic waves propagate in a bulk of a piezoelectric layer. Example BAWresonators include film bulk acoustic wave resonators (FBARs) andsolidly mounted resonators (SMRs).

Although various BAW devices exist, there remains a need for improvedBAW devices and filters.

SUMMARY OF CERTAIN ASPECTS

Certain example aspects are summarized below for illustrative purposes.The innovations are not limited to the specific implementations recitedherein. The innovations described herein can have several novel aspects,no single one of which is solely responsible for its desirableattributes or essential.

Various embodiments disclosed herein can relate to a bulk acoustic wavedevice that includes a first electrode, a second electrode, apiezoelectric layer between the first electrode and the secondelectrode, and a raised frame structure that includes a first raisedframe layer and a second raised frame layer. The second raised framelayer can have a higher acoustic impedance than the first raised framelayer. The second raised frame layer can overlapping a portion of thefirst raised frame layer. The first raised frame layer can extendfurther inward than the second raised frame layer.

The first raised frame layer can extend further inward than the secondraised frame layer by a distance that is between about 50% and about100% of the combined thickness of the first electrode, the piezoelectriclayer, and the second electrode. The first raised frame layer can extendfurther inward than the second raised frame layer by a distance that isbetween about 60% and about 90% of the combined thickness of the firstelectrode, the piezoelectric layer, and the second electrode.

The first raised frame layer can include a non-gradient portion with asubstantially uniform thickness and a gradient portion with a taperedthickness. The non-gradient portion of the first raised frame layer canextend further inward than the second raised frame layer. Thenon-gradient portion of the first raised frame layer can have a widththat is larger than a combined thickness of the first electrode, thepiezoelectric layer, and the second electrode. The non-gradient portionof the first raised frame layer can be between about 1.5 and about 2.5times larger than the combined thickness of the first electrode, thepiezoelectric layer, and the second electrode. The second raised framelayer can include a non-gradient portion with a substantially uniformthickness and a gradient portion with a tapered thickness. Thenon-gradient portion of the first raised frame layer can be wider thanthe non-gradient portion of the second raised frame layer. Thenon-gradient portion of the first raised frame layer can be about 2times to about 8 times wider than the non-gradient portion of the secondraised frame layer. The non-gradient portion of the first raised framelayer can be about 4 times to about 6 times wider than the non-gradientportion of the second raised frame layer. The non-gradient portion ofthe first raised frame layer can be about 4.5 times to about 5.5 timeswider than the non-gradient portion of the second raised frame layer. Agradient angle of the gradient portion of the first raised frame layercan be larger than a gradient angle of the gradient portion of thesecond raised frame layer. A width of the gradient portion of the firstraised frame layer can be less than a width of the gradient portion ofthe second raised frame layer. The non-gradient portion of the firstraised frame layer extends further inward than the gradient portion ofthe second raised frame layer by a distance that is between about 25%and about 75% of the combined thickness of the first electrode, thepiezoelectric layer, and the second electrode. The non-gradient portionof the first raised frame layer can extend further inward than thegradient portion of the second raised frame layer by a distance that isbetween about 35% and about 60% of the combined thickness of the firstelectrode, the piezoelectric layer, and the second electrode. Thenon-gradient portion of the first raised frame layer can extend furtherinward than the gradient portion of the second raised frame layer by adistance that is between about 40% and about 45% of the combinedthickness of the first electrode, the piezoelectric layer, and thesecond electrode.

The first raised frame layer can have a thickness between about 0.02 toabout 0.4 times the combined thickness of the first electrode, thepiezoelectric layer, and the second electrode. The first raised framelayer can have a thickness between about 0.06 to about 0.15 times thecombined thickness of the first electrode, the piezoelectric layer, andthe second electrode. The second raised frame layer can have a thicknessbetween about 0.02 to about 0.4 times the combined thickness of thefirst electrode, the piezoelectric layer, and the second electrode. Thesecond raised frame layer can have a thickness between about 0.06 toabout 0.15 times the combined thickness of the first electrode, thepiezoelectric layer, and the second electrode.

The bulk acoustic wave device can have an active region where the firstelectrode overlaps the second electrode, the active region including amiddle area, and the raised frame structure positioned outside themiddle area of the active region. The combined thickness of the firstelectrode, the piezoelectric layer, and the second electrode can betaken at the middle area of the active region. The bulk acoustic wavedevice can include a recessed frame region between the raised framestructure and the middle area. The bulk acoustic wave device can have apassivation layer over the first electrode, the second electrode, thepiezoelectric layer, and/or the raised frame structure. The passivationlayer can be thinner at the recessed frame region than at the middlearea. The second raised frame layer can be thinner than the firstelectrode. The second raised frame layer can be thinner than the secondelectrode.

The first raised frame layer can be between the first electrode and thesecond electrode. The piezoelectric layer can be over the firstelectrode, the second electrode an be over the piezoelectric layer, andthe first raised frame layer can be between the second electrode and thepiezoelectric layer. The second raised frame layer can be over thesecond electrode. The piezoelectric layer can be over the firstelectrode, the second electrode can be over the piezoelectric layer, andthe first raised frame layer can be between the first electrode and thepiezoelectric layer. The second raised frame layer can be over thesecond electrode.

The first raised frame layer can have a lower acoustic impedance thanthe first electrode. The first raised frame layer can have a loweracoustic impedance than the second electrode. The first raised framelayer can have a lower acoustic impedance than the piezoelectric layer.The first raised frame layer can include silicon dioxide. The secondraised frame layer can include the same material as the secondelectrode. The second raised frame layer can include at least one ofmolybdenum, tungsten, ruthenium, platinum, or iridium.

The bulk acoustic wave device can include a cavity, and the firstelectrode can be between the cavity and the piezoelectric layer. Thebulk acoustic wave device can include an acoustic Bragg reflector, andthe first electrode can be between the acoustic Bragg reflector and thepiezoelectric layer.

Various embodiments disclosed herein can relate to a bulk acoustic wavedevice, which can include a first electrode, a second electrode, apiezoelectric layer between the first electrode and the secondelectrode, and a raised frame structure that includes a raised framelayer having a lower acoustic impedance than at least one of the firstelectrode, the second electrode, and the piezoelectric layer.

The width of the raised frame layer that overlaps the first and secondelectrodes can be between about 1.5 times to about 4 times larger thanthe combined thickness of the first electrode, the piezoelectric layer,and the second electrode. The width of the raised frame layer thatoverlaps the first and second electrodes can be between about 2 times toabout 3 times wider than the combined thickness of the first electrode,the piezoelectric layer, and the second electrode.

The raised frame layer can include a non-gradient portion with asubstantially uniform thickness and a gradient portion with a taperedthickness. The non-gradient portion of the raised frame layer can have awidth that is larger than a combined thickness of the first electrode,the piezoelectric layer, and the second electrode. The non-gradientportion of the raised frame layer can be between about 1.5 and about 2.5times larger than the combined thickness of the first electrode, thepiezoelectric layer, and the second electrode. The raised frame layercan have a thickness between about 0.02 to about 0.4 times the combinedthickness of the first electrode, the piezoelectric layer, and thesecond electrode. The raised frame layer can have a thickness betweenabout 0.06 to about 0.15 times the combined thickness of the firstelectrode, the piezoelectric layer, and the second electrode.

The bulk acoustic wave device can have an active region where the firstelectrode overlaps the second electrode. The active region can include amiddle area, and the raised frame structure can be positioned outsidethe middle area of the active region. The combined thickness of thefirst electrode, the piezoelectric layer, and the second electrode canbe taken at the middle area of the active region. The bulk acoustic wavedevice can include a recessed frame region between the raised framestructure and the middle area. The bulk acoustic wave device can includea passivation layer over the first electrode, the second electrode, thepiezoelectric layer, and/or the raised frame structure. The passivationlayer can be thinner at the recessed frame region than at the middlearea.

The raised frame layer can be between the first electrode and the secondelectrode. The piezoelectric layer can be over the first electrode. Thesecond electrode can be over the piezoelectric layer. The raised framelayer can be between the second electrode and the piezoelectric layer.The piezoelectric layer can be over the first electrode. The secondelectrode can be over the piezoelectric layer. The raised frame layercan be between the first electrode and the piezoelectric layer.

The raised frame layer can have a lower acoustic impedance than thefirst electrode. The raised frame layer can have a lower acousticimpedance than the second electrode. The raised frame layer can have alower acoustic impedance than the piezoelectric layer. The raised framelayer can include silicon dioxide.

The bulk acoustic wave device can include a cavity, and the firstelectrode can be between the cavity and the piezoelectric layer. Thebulk acoustic wave device can include an acoustic Bragg reflector, andthe first electrode can be between the acoustic Bragg reflector and thepiezoelectric layer.

Various embodiments disclosed herein can relate to a filter (e.g., aband pass filter), which can include one or more series bulk acousticwave (BAW) resonators that include a first raised frame structure. Thefirst raised frame structure can have a first raised frame layer and asecond raised frame layer having a higher acoustic impedance than thefirst raised frame layer. The second raised frame layer can overlap aportion of the first raised frame layer. The first raised frame layercan extend further inward than the second raised frame layer. The filtercan include one or more shunt bulk acoustic wave (BAW) resonators thathave a second raised frame structure different from the first raisedframe structure.

The filter can include a plurality of the series BAW resonators that canbe coupled in series between a first port and a second port. The filtercan include a plurality of the shunt BAW resonators that can be coupledin parallel between the series BAW resonators and ground.

The series BAW resonators can include a first electrode, a secondelectrode, and a piezoelectric layer, which can be between the firstelectrode and the second electrode. The first raised frame layer canextend further inward than the second raised frame layer by a distancethat can be between about 50% and about 100% of the combined thicknessof the first electrode, the piezoelectric layer, and the secondelectrode. The first raised frame layer can extend further inward thanthe second raised frame layer by a distance that can be between about60% and about 90% of the combined thickness of the first electrode, thepiezoelectric layer, and the second electrode.

The first raised frame layer can include a non-gradient portion with asubstantially uniform thickness and a gradient portion with a taperedthickness. The non-gradient portion of the first raised frame layer canextend further inward than the second raised frame layer. Thenon-gradient portion of the first raised frame layer can have a widththat is larger than a combined thickness of the first electrode, thepiezoelectric layer, and the second electrode. The non-gradient portionof the first raised frame layer can be between about 1.5 and about 2.5times larger than the combined thickness of the first electrode, thepiezoelectric layer, and the second electrode. The second raised framelayer can include a non-gradient portion with a substantially uniformthickness and a gradient portion with a tapered thickness. Thenon-gradient portion of the first raised frame layer can be wider thanthe non-gradient portion of the second raised frame layer. Thenon-gradient portion of the first raised frame layer can be about 2times to about 8 times wider than the non-gradient portion of the secondraised frame layer. The non-gradient portion of the first raised framelayer can be about 4 times to about 6 times wider than the non-gradientportion of the second raised frame layer. The non-gradient portion ofthe first raised frame layer can be about 4.5 times to about 5.5 timeswider than the non-gradient portion of the second raised frame layer. Agradient angle of the gradient portion of the first raised frame layeris larger than a gradient angle of the gradient portion of the secondraised frame layer. A width of the gradient portion of the first raisedframe layer can be less than a width of the gradient portion of thesecond raised frame layer. The non-gradient portion of the first raisedframe layer can extend further inward than the gradient portion of thesecond raised frame layer by a distance that is between about 25% andabout 75% of the combined thickness of the first electrode, thepiezoelectric layer, and the second electrode. The non-gradient portionof the first raised frame layer can extend further inward than thegradient portion of the second raised frame layer by a distance that isbetween about 35% and about 60% of the combined thickness of the firstelectrode, the piezoelectric layer, and the second electrode. Thenon-gradient portion of the first raised frame layer can extend furtherinward than the gradient portion of the second raised frame layer by adistance that is between about 40% and about 45% of the combinedthickness of the first electrode, the piezoelectric layer, and thesecond electrode.

The first raised frame layer can have a thickness between about 0.02 toabout 0.4 times the combined thickness of the first electrode, thepiezoelectric layer, and the second electrode. The first raised framelayer can have a thickness between about 0.06 to about 0.15 times thecombined thickness of the first electrode, the piezoelectric layer, andthe second electrode.

The filter can include an active region where the first electrodeoverlaps the second electrode, the active region including a middlearea. The raised frame structure can be positioned outside the middlearea of the active region. The combined thickness of the firstelectrode, the piezoelectric layer, and the second electrode can be atthe middle area of the active region.

The second raised frame layer can be thinner than the first electrode.The second raised frame layer can be thinner than the second electrode.The first raised frame layer can be between the first electrode and thesecond electrode. The piezoelectric layer can be over the firstelectrode, the second electrode can be over the piezoelectric layer, andthe first raised frame layer can be between the second electrode and thepiezoelectric layer. The second raised frame layer can be over thesecond electrode. The piezoelectric layer can be over the firstelectrode, the second electrode can be over the piezoelectric layer, andthe first raised frame layer can be between the first electrode and thepiezoelectric layer. The second raised frame layer can be over thesecond electrode.

The first raised frame layer can have a lower acoustic impedance thanthe first electrode. The first raised frame layer can have a loweracoustic impedance than the second electrode. The first raised framelayer can have a lower acoustic impedance than the piezoelectric layer.The first raised frame layer can include silicon dioxide. The secondraised frame structure of the one or more shunt BAW resonators caninclude a first raised frame layer and a second raised frame layerhaving a higher acoustic impedance than the first raised frame layer.The second raised frame layer can overlap a portion of the first raisedframe layer. The second raised frame layer can extend further inwardthan the first raised frame layer.

Various embodiments disclosed herein can relate to a filter (e.g., aband rejection filter), which can include one or more series bulkacoustic wave (BAW) resonators that include a first raised framestructure, one or more shunt bulk acoustic wave (BAW) resonators thathave a second raised frame structure different from the first raisedframe structure. The second raised frame structure can include a firstraised frame layer and a second raised frame layer having a higheracoustic impedance than the first raised frame layer. The second raisedframe layer can overlap a portion of the first raised frame layer. Thefirst raised frame layer can extend further inward than the secondraised frame layer. The filter can include a plurality of the series BAWresonators that can be coupled in series between a first port and asecond port. The filter can include a plurality of the shunt BAWresonators that can be coupled in parallel between the series BAWresonators and ground. The shunt BAW resonators can include a firstelectrode, a second electrode, and a piezoelectric layer between thefirst electrode and the second electrode. The first raised frame layercan extend further inward than the second raised frame layer by adistance that is between about 50% and about 100% of the combinedthickness of the first electrode, the piezoelectric layer, and thesecond electrode. The first raised frame layer can extend further inwardthan the second raised frame layer by a distance that is between about60% and about 90% of the combined thickness of the first electrode, thepiezoelectric layer, and the second electrode.

The first raised frame layer can include a non-gradient portion with asubstantially uniform thickness and a gradient portion with a taperedthickness. The non-gradient portion of the first raised frame layer canextend further inward than the second raised frame layer. Thenon-gradient portion of the first raised frame layer can have a widththat is larger than a combined thickness of the first electrode, thepiezoelectric layer, and the second electrode. The non-gradient portionof the first raised frame layer can be between about 1.5 and about 2.5times larger than the combined thickness of the first electrode, thepiezoelectric layer, and the second electrode. The second raised framelayer can include a non-gradient portion with a substantially uniformthickness and a gradient portion with a tapered thickness. Thenon-gradient portion of the first raised frame layer is wider than thenon-gradient portion of the second raised frame layer. The non-gradientportion of the first raised frame layer can be about 2 times to about 8times wider than the non-gradient portion of the second raised framelayer. The non-gradient portion of the first raised frame layer can beabout 4 times to about 6 times wider than the non-gradient portion ofthe second raised frame layer. The non-gradient portion of the firstraised frame layer can be about 4.5 times to about 5.5 times wider thanthe non-gradient portion of the second raised frame layer. A gradientangle of the gradient portion of the first raised frame layer can belarger than a gradient angle of the gradient portion of the secondraised frame layer. A width of the gradient portion of the first raisedframe layer can be less than a width of the gradient portion of thesecond raised frame layer. The non-gradient portion of the first raisedframe layer can extend further inward than the gradient portion of thesecond raised frame layer by a distance that is between about 25% andabout 75% of the combined thickness of the first electrode, thepiezoelectric layer, and the second electrode. The non-gradient portionof the first raised frame layer can extend further inward than thegradient portion of the second raised frame layer by a distance that isbetween about 35% and about 60% of the combined thickness of the firstelectrode, the piezoelectric layer, and the second electrode. Thenon-gradient portion of the first raised frame layer can extend furtherinward than the gradient portion of the second raised frame layer by adistance that is between about 40% and about 45% of the combinedthickness of the first electrode, the piezoelectric layer, and thesecond electrode.

The first raised frame layer can have a thickness between about 0.02 toabout 0.4 times the combined thickness of the first electrode, thepiezoelectric layer, and the second electrode. The first raised framelayer can have a thickness between about 0.06 to about 0.15 times thecombined thickness of the first electrode, the piezoelectric layer, andthe second electrode.

The filter can have an active region where the first electrode overlapsthe second electrode. The active region can have a middle area. Theraised frame structure can be positioned outside the middle area of theactive region. The combined thickness of the first electrode, thepiezoelectric layer, and the second electrode can be at the middle areaof the active region. The second raised frame layer can be thinner thanthe first electrode. The second raised frame layer can be thinner thanthe second electrode. The first raised frame layer can be between thefirst electrode and the second electrode. The piezoelectric layer can beover the first electrode, the second electrode can be over thepiezoelectric layer, and the first raised frame layer can be between thesecond electrode and the piezoelectric layer. The second raised framelayer can be over the second electrode. The piezoelectric layer can beover the first electrode, the second electrode can be over thepiezoelectric layer, and the first raised frame layer can be between thefirst electrode and the piezoelectric layer. The second raised framelayer can be over the second electrode.

The first raised frame layer can have a lower acoustic impedance thanthe first electrode. The first raised frame layer can have a loweracoustic impedance than the second electrode. The first raised framelayer can have a lower acoustic impedance than the piezoelectric layer.The first raised frame layer can include silicon dioxide. The secondraised frame structure of the one or more series BAW resonators caninclude a first raised frame layer and a second raised frame layerhaving a higher acoustic impedance than the first raised frame layer.The second raised frame layer can overlap a portion of the first raisedframe layer. The second raised frame layer can extend further inwardthan the first raised frame layer.

Various embodiments disclosed herein can relate to a filter thatincludes one or more series bulk acoustic wave (BAW) resonators thatinclude a first raised frame structure and one or more shunt bulkacoustic wave (BAW) resonators that have a second raised frame structuredifferent from the first raised frame structure. The first raised framestructure or the second raised frame structure can include a raisedframe layer having a lower acoustic impedance than at least one of afirst electrode, a second electrode, and a piezoelectric layer of thecorresponding BAW resonator. A width of the raised frame layer thatoverlaps the first and second electrodes can be between about 1.5 timesto about 4 times larger than the combined thickness of the firstelectrode, the piezoelectric layer, and the second electrode.

The first raised frame structure can have the raised frame layer. Thefilter can be a band pass filter. The second raised frame structure canhave the raised frame layer. The filter can be a band stop filter. Thefilter can have a plurality of the series BAW resonators that arecoupled in series between a first port and a second port. The filter canhave a plurality of the shunt BAW resonators that are coupled inparallel between the series BAW resonators and ground.

The raised frame layer can include a non-gradient portion with asubstantially uniform thickness and a gradient portion with a taperedthickness. The non-gradient portion of the first raised frame layer canhave a width that is larger than a combined thickness of the firstelectrode, the piezoelectric layer, and the second electrode. Thenon-gradient portion of the raised frame layer can be between about 1.5and about 2.5 times larger than the combined thickness of the firstelectrode, the piezoelectric layer, and the second electrode. The raisedframe layer can have a thickness between about 0.02 to about 0.4 timesthe combined thickness of the first electrode, the piezoelectric layer,and the second electrode. The first raised frame layer can have athickness between about 0.06 to about 0.15 times the combined thicknessof the first electrode, the piezoelectric layer, and the secondelectrode. The filter can include an active region where the firstelectrode overlaps the second electrode. The active region can have amiddle area, and the raised frame structure can be positioned outsidethe middle area of the active region. The combined thickness of thefirst electrode, the piezoelectric layer, and the second electrode canbe taken at the middle area of the active region.

The raised frame layer can be between the first electrode and the secondelectrode. The piezoelectric layer can be over the first electrode, thesecond electrode can be over the piezoelectric layer, and the raisedframe layer can be between the second electrode and the piezoelectriclayer. The piezoelectric layer can be over the first electrode, thesecond electrode can be over the piezoelectric layer, and the raisedframe layer can be between the first electrode and the piezoelectriclayer. The raised frame layer can have a lower acoustic impedance thanthe first electrode. The raised frame layer can have a lower acousticimpedance than the second electrode. The raised frame layer can have alower acoustic impedance than the piezoelectric layer. The raised framelayer can include silicon dioxide.

A band pass filter can include one or more of the bulk acoustic wavedevices disclosed herein. A band stop filter can include one or more ofthe bulk acoustic wave devices disclosed herein. A ladder filter caninclude one or more of the bulk acoustic wave devices disclosed herein.A lattice filter can include one or more of the bulk acoustic wavedevices disclosed herein. A diplexer can include one or more of the bulkacoustic wave devices disclosed herein. A duplexer can include one ormore of the bulk acoustic wave devices disclosed herein. A multiplexercan include one or more of the bulk acoustic wave devices disclosedherein. A switching multiplexer can include one or more of the bulkacoustic wave devices disclosed herein.

A radio frequency module can include an acoustic wave die including atleast one filter, the at least one filter can include one or more of thebulk acoustic wave devices disclosed herein. The radio frequency modulecan include a radio frequency circuit element that can be coupled to theacoustic wave die. The acoustic wave die and the radio frequency circuitelement can be enclosed within a common module package.

A wireless communication device can include an acoustic wave filter thatcan have one or more of the bulk acoustic wave devices disclosed herein,an antenna operatively coupled to the acoustic wave filter, a radiofrequency amplifier operatively coupled to the acoustic wave filter andconfigured to amplify a radio frequency signal, and a transceiver incommunication with the radio frequency amplifier. The wirelesscommunication device can include a baseband processor in communicationwith the transceiver. The acoustic wave filter can be included in aradio frequency front end. The wireless communication device can be auser equipment.

A wireless communication device can include an acoustic wave die havingat least one filter that includes one or more of the bulk acoustic wavedevices disclosed herein, an antenna operatively coupled to an acousticwave filter, a radio frequency amplifier operatively coupled to theacoustic wave filter and configured to amplify a radio frequency signal,and a transceiver in communication with the radio frequency amplifier.The wireless communication device can include a baseband processor incommunication with the transceiver. The acoustic wave filter can beincluded in a radio frequency front end. The wireless communicationdevice can be a user equipment.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of this disclosure will now be described, by way ofnon-limiting example, with reference to the accompanying drawings, likereference numerals can refer to similar features throughout.

FIG. 1 is a plan view of an example embodiment of a raised frame bulkacoustic wave device.

FIG. 2 is a cross-sectional view of an example embodiment of a raisedframe bulk acoustic wave device.

FIG. 3 is a cross-sectional view of an example raised frame bulkacoustic wave device.

FIG. 4 is a cross-sectional view of another example raised frame bulkacoustic wave device.

FIG. 5 is a partial cross-sectional view of an example raised frame bulkacoustic wave device.

FIGS. 6 and 7 are graphs showing simulated results for the raised framebulk acoustic wave device of FIG. 5.

FIG. 8 is a partial cross-sectional view of an example raised frame bulkacoustic wave device.

FIGS. 9 and 10 are graphs showing simulated results for the raised framebulk acoustic wave device of FIG. 8.

FIG. 11 is a partial cross-sectional view of an example raised framebulk acoustic wave device.

FIGS. 12 and 13 are graphs showing simulated results for the raisedframe bulk acoustic wave device of FIG. 11.

FIG. 14 is a partial cross-sectional view of an example raised framebulk acoustic wave device.

FIGS. 15 and 16 are graphs showing simulated results for the raisedframe bulk acoustic wave device of FIG. 5.

FIG. 17 is a graph that combines the results of FIGS. 6, 9, 12, and 15.

FIG. 18 is a graph that combines the results of FIGS. 7, 10, 13, and 16.

FIG. 19 is a graph that shows results for simulated filter response fora ladder filter that uses the BAW device of FIG. 5.

FIG. 20 is a graph that shows results for simulated filter response fora ladder filter that uses the BAW device of FIG. 8.

FIG. 21 is a graph that shows results for simulated filter response fora ladder filter that uses the BAW device of FIG. 11.

FIG. 22 is a graph that shows results for simulated filter response fora ladder filter that uses the BAW device of FIG. 14.

FIG. 23 is a graph that shows results for simulated filter response fora ladder filter that uses the BAW devices of FIGS. 8 and 11.

FIG. 24 is a graph that combines the results of FIGS. 19 to 23.

FIG. 25 is a graph that shows simulated results for BAW devices withvarying width of the first raised frame layer.

FIG. 26 is a graph that shows simulated results for BAW devices withvarying thickness for the second raised frame layer.

FIG. 27 is a graph that shows simulated results for BAW devices withvarying thickness for the first raised frame layer.

FIG. 28 is a graph that shows simulated results for BAW devices withvarying width for the second raised frame layer.

FIG. 29 is a graph that shows simulated results for BAW devices withvarying thickness for the first raised frame layer.

FIG. 30 is a graph that shows simulated results for BAW devices withvarying thickness for the first raised frame layer, where the secondraised frame layer is omitted.

FIG. 31 shows an example gradient angle.

FIG. 32 is a cross-sectional view of another example embodiment of araised frame bulk acoustic wave device.

FIG. 33 is a schematic diagram of an example of an acoustic wave ladderfilter.

FIG. 34 is a schematic diagram of an example of a duplexer.

FIG. 35 is a schematic diagram of an example of a multiplexer.

FIG. 36 is a schematic block diagram of a module that includes anantenna switch and duplexers that include one or more raised frame bulkacoustic wave devices.

FIG. 37A is a schematic block diagram of a module that includes a poweramplifier, a radio frequency switch, and duplexers that include one ormore raised frame bulk acoustic wave devices.

FIG. 37B is a schematic block diagram of a module that includes a lownoise amplifier, a radio frequency switch, and acoustic wave filters tinclude one or more raised frame bulk acoustic wave devices.

FIG. 38 is a schematic block diagram of a module that includes a poweramplifier, a radio frequency switch, a duplexer that includes one ormore raised frame bulk acoustic wave devices.

FIG. 39A is a schematic block diagram of a wireless communication devicethat includes filters that include one or more raised frame bulkacoustic wave devices.

FIG. 39B is a schematic block diagram of another wireless communicationdevice that includes filters that include one or more raised frame bulkacoustic wave devices.

DETAILED DESCRIPTION OF CERTAIN EMBODIMENTS

The following description of certain embodiments presents variousdescriptions of specific embodiments. However, the innovations describedherein can be embodied in a multitude of different ways, for example, asdefined and covered by the claims. In this description, reference ismade to the drawings where like reference numerals can indicateidentical or functionally similar elements. It will be understood thatelements illustrated in the figures are not necessarily drawn to scale.Moreover, it will be understood that certain embodiments can includemore elements than illustrated in a drawing and/or a subset of theelements illustrated in a drawing. Further, some embodiments canincorporate any suitable combination of features from two or moredrawings.

For developing high performance bulk acoustic wave (BAW) filters, a highquality factor (Q) can be generally desirable. Bulk acoustic wave (BAW)devices can include raised frame structures. A raised frame structurecan reduce lateral energy leakage from a main acoustically active regionof the bulk acoustic wave device. For example, a BAW device can includea multi-layer raised frame structure, in some implementations. A BAWdevice can include a raised frame structure with a first layer thatincludes a material with a relatively low acoustic impedance (e.g.,lower than one or both of the electrodes and/or the piezoelectriclayer), such as silicon dioxide. The raised frame structure of the BAWdevice can include a second layer that includes a material with arelatively high acoustic impedance (e.g., higher than the first layerand/or the same or higher than one or both of the electrodes and/or thepiezoelectric layer). A BAW device can include a single-layer raisedframe structure, in some implementations. For example, the single-layerraised frame structure can include a layer with a relatively lowacoustic impedance, or a layer with a relatively high acousticimpedance. The raised frame structure of the BAW device can facilitateachieving a relatively high Q, such as in a region above a resonantfrequency and/or above an anti-resonant frequency. BAW devices with theraised frame structures disclosed herein can achieve low insertion lossand/or low Gamma loss, in some cases.

To achieve a high Q, a raised frame, which can be referred to as aborder ring, can block lateral energy leakage from an active domain of aBAW resonator to a passive domain of the BAW resonator. A raised framecan improve Q, although it may not be able to trap all leakage energy.In some instances, the raised frame can generate a relatively largespurious mode, which can be referred to as a raised frame mode, whichcan be below a main resonant frequency of a BAW resonator. This cancause Gamma degradation in carrier aggregation bands for a filter. Gammacan refer to a reflection coefficient. The raised frame structure can beconfigured to suppress the spurious mode or raised frame mode, which canimprove Q, such as below the resonant frequency, as discussed herein.

Some aspects of this disclosure relate to a bulk acoustic wave resonatorthat includes a raised frame structure that can achieve low insertionloss and/or low Gamma loss. The raised frame structure can be disposedoutside or along a perimeter of an active region of the bulk acousticwave resonator. The raised frame can include a material with relativelylow acoustic impedance, which can be configured to provide low insertionloss and/or low Gamma loss. In some implementations, the multi-layerraised frame structure can include a first raised frame layer and asecond raised frame layer. The first raised frame layer can include arelatively low acoustic impedance material, such as silicon dioxide,disposed between electrodes that are on opposing sides of apiezoelectric layer. For instance, the low acoustic impedance materialcan be disposed between a top electrode and a piezoelectric layer of abulk acoustic wave resonator. The second raised frame layer can includea relatively high acoustic impedance material. The second raised framelayer can include a material this is heavier or more dense than thematerial of the first raised frame layer. In some cases, the secondraised frame layer can be the same material as an electrode of the bulkacoustic wave resonator. The first raised frame layer (e.g., having arelatively low acoustic impedance) can extend further inward than thesecond raised frame layer (e.g., having a relatively high acousticimpedance). This raised frame configuration can suppress the spurious orraised frame mode without heavy degradation above the resonantfrequency. The raised frame structures disclosed herein can provideimproved Q below the resonant frequency, while maintaining a high Qabove the resonant frequency.

In some implementations, a low Gamma loss can be achieved with a raisedframe spurious mode away from carrier aggregation bands. Due to the lowacoustic impedance material, the frequency of the raised frame domaingenerating a relatively strong raised frame spurious mode can besignificantly lower than for other types of BAW devices. The lowacoustic impedance material can be configured so that the raised framemode for the raised frame structure can be outside of a carrieraggregation band so as not to provide a Gamma loss, or to provide lowGamma loss, in some cases. By way of example, in a carrier aggregationapplication, a multiplexer can include a common node arranged to receivea carrier aggregation signal, a first filter having a passbandassociated with a first carrier of the carrier aggregation signal, and asecond filter coupled to the first filter at the common node and havinga second passband associated with a second carrier of the carrieraggregation signal. The first filter can include a BAW resonator with araised frame structure as disclosed herein, which can increase Gamma forthe first filter in the passband of the second filter.

Also, some raised frame structures disclosed herein can have a lowacoustic impedance material configured so that the difference betweenthe effective acoustic impedance of the raised frame domain and theactive domain can provide a high Q. In some embodiments, the raisedframe structure can provide a high mode reflection of a lateral energyand can decrease mode conversion from main mode to other lateral modesaround the anti-resonance frequency. Accordingly, the configuration of alow acoustic impedance layer or material in the raised frame structurecan cause Q to be significantly increased, such as relative to other BAWdevices or other raised frame structures.

Although some embodiments disclosed herein may be discussed withreference to dual raised frame structures with two raised frame layers,various suitable principles and advantages discussed herein can beapplied to a single-layer raised frame structures or multi-layer raisedframe structure that includes two or three or more raised frame layers.

FIG. 1 is a plan view of a raised frame bulk acoustic wave device 100.As shown in FIG. 1, the bulk acoustic wave device 100 can include araised frame zone 102 around the perimeter of an active region of thebulk acoustic wave device 100. The raised frame zone 200 can be referredto as a border ring in certain instances. A raised frame structure canbe in the raised frame zone 200. The raised frame structure can beimplemented in accordance with any suitable principles and advantages ofthe raised frame bulk acoustic wave devices disclosed herein. The raisedframe structure can be outside of a middle area 400 of the active regionof the bulk acoustic wave device 100. A raised frame layer can be in theraised frame zone 200 and can extend above a metal electrode. FIG. 1illustrates the metal electrode at the middle area 400 and the raisedframe layer at the raised frame zone 200. One or more other layers canbe included over the metal electrode and the raised frame layer. Forinstance, silicon dioxide can be included over the metal electrode andthe raised frame layer. FIG. 1 also illustrates that a piezoelectriclayer 600 of the bulk acoustic wave device 100 can be below the metalelectrode and the raised frame layer.

Some embodiments of raised frame bulk acoustic wave devices will bediscussed with reference to example cross sections along the line from Ato A′ in FIG. 1. Any suitable combination of features of the bulkacoustic wave devices disclosed herein can be combined with each other.Any of the bulk acoustic wave devices disclosed herein can be a bulkacoustic wave resonator in a filter, such as arranged to filter a radiofrequency signal.

FIG. 2 is a schematic cross-sectional view of an example of a bulkacoustic wave (BAW) device 100 with a dual-layer raised frame structure.The BAW device 100 can includes a support substrate 110, a cavity 112, afirst or lower electrode 114 positioned over the support substrate 110,a piezoelectric layer 116 positioned over the lower electrode 114, asecond or upper electrode 118 positioned over the piezoelectric layer116, a first raised frame structure or layer 120 positioned at leastpartially between the piezoelectric layer 116 and the upper electrode118, a second raised frame structure or layer 122 positioned over theupper electrode 118, and a passivation layer 124 positioned over thesecond raised frame structure 122.

The support substrate 110 can be a silicon substrate, and other suitablesubstrates can alternatively be implemented in place of the siliconsubstrate. One or more layers, such as a passivation layer, can bepositioned between the lower electrode 114 and the support substrate110. In some embodiments, the cavity 112 can be an air cavity.

The piezoelectric layer 116 can be disposed between the first electrode114 and the second electrode 118. The piezoelectric layer 116 can be analuminum nitride (AlN) layer or any other suitable piezoelectric layer.An active region 130 or active domain of the BAW device 100 can bedefined by the portion of the piezoelectric layer 116 that overlaps withboth the lower electrode 114 and the upper electrode 118, for exampleover an acoustic reflector, such as the cavity 112. The lower electrode114 and/or the upper electrode 118 can have a relatively high acousticimpedance. For example, the lower electrode 114 and/or the upperelectrode 118 can include molybdenum (Mo), tungsten (W), ruthenium (Ru),iridium (Ir), platinum (Pt), Ir/Pt, or any suitable alloy and/orcombination thereof, although other suitable conductive materials couldbe used. The upper electrode 118 can be formed of the same material asthe lower electrode 114 in certain instances, although differentmaterials can be used for the lower electrode 114 and the upperelectrode 118, in some cases.

The illustrated BAW device 100 can include an active region 130 that hasa main acoustically active region 132 and a raised frame region 134 atleast partially, or fully, surrounding the main acoustically activeregion 132 (e.g., in plan view). In the cross-sectional view of FIG. 2,the raised frame region 134 can be on opposing sides of the mainacoustically active region 132. The main acoustically active region 132may be referred to as a center region or middle area of the activeregion 130. The main acoustically active region 132 can set the mainresonant frequency of the BAW device 100. There can be a significant(e.g., exponential) fall off of acoustic energy in the piezoelectriclayer 116 for a main mode in the frame region 134 relative to the mainacoustically active region 132. A recessed frame region 136 can bepositioned between the main acoustically active region 132 and theraised frame region 134.

In some embodiments, the raised frame structure of the BAW device can bea dual-layer raised frame structure. The dual-layer raised framestructure of the BAW device 100 can include the first raised framestructure or layer 120 and the second raised frame structure or layer122. The first raised frame layer 120 and the second raised frame layer122 can at least partially overlap with each other in the active region130 of the BAW device 100. A raised frame region 134 or domain of theBAW device 100 can be defined by the portion of the raised framestructure in the active region 130 of the BAW 100. At least a portion ofthe raised frame structure can be included in an active region 130 ofthe BAW device 100.

The first raised frame layer 120 can be positioned between the first orlower electrode 114 and the second or upper electrode 118. Asillustrated in FIG. 2, the first raised frame layer 120 can bepositioned between the piezoelectric layer 116 and the second electrode118. The first raised frame layer 120 can extend beyond the activeregion of the bulk acoustic wave device 100 as shown in FIG. 2, whichcan be beneficial for manufacturability reasons in certain instances.The first raised frame layer 120 can have a non-gradient portion 138 anda gradient portion 140. The non-gradient portion of the first raisedframe layer 120 (e.g., the upper surface thereof) can be substantiallyparallel to the piezoelectric layer 116 (e.g., to the upper surfacethereof). The non-gradient portion 138 of the first raised frame layer120 can have a substantially uniform thickness. The gradient portion 140of the first raised frame layer 120 can be tapered, and can be at an endor edge of the first raised frame layer 120, for example. The uppersurface of the gradient portion 140 of the first raised frame layer 120can form a gradient angle relative to upper surface of the non-gradientportion 138 of the first raised frame layer 120. The gradient portion140 of the first raised frame layer 120 can have a decreasing thicknessmoving along a direction from the raised frame structure toward the mainacoustically active region 132 (or middle area). The gradient portion140 can be inward of the non-gradient portion 138 of the first raisedframe layer 120. The non-gradient portion 138 can at least partially, orcompletely, surround the gradient portion 140 (e.g., in plan view).

The first raised frame layer 120 can be a low acoustic impedancematerial. The low acoustic impedance material can have a lower acousticimpedance than the material of the first electrode 114. The low acousticimpedance material has a lower acoustic impedance than the material ofthe second electrode 118. The low acoustic impedance material can have alower acoustic impedance than the material of the piezoelectric layer116. As an example, the first raised frame layer 120 can be a silicondioxide (SiO2) layer. Since silicon dioxide is already used in a varietyof bulk acoustic wave devices, a silicon dioxide first raised framelayer 120 can be relatively easy to manufacture. Other oxide materialscan be used, and the first raised frame structure or layer 120 can be anoxide raised frame structure or layer. The first raised frame layer 120can be a silicon nitride (SiN) layer, a silicon carbide (SiC) layer, orany other suitable low acoustic impedance layer. The first raised framelayer 120 can have a relatively low density. The density and/or acousticimpedance of the first raised frame layer 120 can be lower than thedensity and/or acoustic impedance of the lower electrode 114, of theupper electrode 118, of the piezoelectric layer 116, and/or of thesecond raised frame layer 122 of the BAW device 100.

The second raised frame layer 122 can at least partially overlap thefirst raised frame layer 120, such as in the active region 130 of theBAW device 100. The second raised frame layer 122 can be positioned overthe upper electrode 118. The upper electrode 118 can be positionedbetween the first raised frame layer 120 and the second raised framelayer 122. The second raised frame layer 122 can extend beyond theactive region of the bulk acoustic wave device 100 as shown in FIG. 2,which can be beneficial for manufacturability reasons in certaininstances. The second raised frame layer 122 can have a non-gradientportion 142 and a gradient portion 144. The non-gradient portion 142 ofthe second raised frame layer 122 (e.g., the upper surface thereof) canbe substantially parallel to the piezoelectric layer 116 (e.g., to theupper surface thereof). The non-gradient portion 142 of the secondraised frame layer 122 can have a substantially uniform thickness. Thegradient portion 144 of the second raised frame layer 122 can betapered, and can be at an end or edge of the second raised frame layer122, for example. The upper surface of the gradient portion 144 of thesecond raised frame layer 122 can form an angle relative to uppersurface of the non-gradient portion 142 of the second raised frame layer122. The gradient portion 144 of the second raised frame layer 122 canhave a decreasing thickness moving along a direction from the raisedframe structure toward the main acoustically active region 132 (ormiddle area). The gradient portion 144 can be inward of the non-gradientportion 142 of the second raised frame layer 122. The non-gradientportion 142 can at least partially, or completely, surround the gradientportion 144 (e.g., in plan view).

The second raised frame layer 122 can be a relatively high acousticimpedance material. The second raised frame layer 122 can include arelatively high density material. For instance, the second raised framelayer 122 can include molybdenum (Mo), tungsten (W), ruthenium (Ru),platinum (Pt), iridium (Ir), the like, or any suitable alloy thereof.The second raised frame layer 122 can be a metal layer. Alternatively,the second raised frame layer 122 can be a suitable non-metal materialwith a relatively high density. The density and/or acoustic impedance ofthe second raised frame layer 122 can be similar to or greater than thedensity and/or acoustic impedance of the lower electrode 114, of theupper electrode 118, of the piezoelectric layer 116, and/or of the firstraised frame layer 120 of the BAW device 100. In some instances, theraised frame structure 20 can be of the same material as the lowerelectrode 114 and/or the upper electrode 118 of the BAW device 100. Insome implementations, the second raised frame layer 122 can be adjacentto the upper electrode 118. The upper electrode 118 can have asubstantially uniform thickness, although in some cases it may be angled(e.g., downward or toward the piezoelectric layer 116). The secondraised frame layer 122 can be a thickened region of the same materialthat makes up the upper electrode 118. The upper electrode 118 and thesecond raised frame layer 122 can be formed by different processingsteps, and in some cases the can be a resulting identifiable transitionbetween the upper electrode 118 and the second raised frame layer 122 ofthe same material, although some implementations may not have anidentifiable transition between the upper electrode and the secondraised frame layer 122.

The second raised frame layer 122 can increase the height of the BAWdevice 100 in the raised frame region 134. Accordingly, the BAW device100 can have a greater height in the raised frame region 134 than inother portions of the active region 130, such as the middle area of theactive domain. Forming the second raised frame layer 122 over the upperor second electrode 118 can be relatively easy from a manufacturingperspective. However, in some other embodiments, a second raised framelayer 122 can be included in a different position in the stack of layersin the raised frame domain.

The passivation layer 124 can be positioned over the upper electrode 118and/or over the second raised frame layer 122. The passivation layer 124can be a silicon dioxide layer, although any suitable passivationmaterial can be used. The passivation layer 124 can be formed withdifferent thicknesses in different regions of the BAW device 100. Forexample, as shown in FIG. 2, the passivation layer 124 can be thinner inthe recessed frame region 136 than in the main acoustically activeregion 132, or than in other portions such as the raised frame region134. In some cases, the recessed frame region 136 can contribute toachieving the relatively high Q, such as below the resonant frequency.By way of example, the combination of the recessed frame region 136 andthe raised frame structure of the BAW device 100 can contribute toachieving the relatively high Q, such as below the resonant frequency.In some embodiments, the recessed frame region 136 can be omitted, suchas by using a passivation layer 124 that has a substantially uniformthickness. Also, in some embodiments, the passivation layer 124 can beomitted.

The passivation layer 124 can have a non-gradient portion 146 and agradient portion 148. The non-gradient portion 146 of the passivationlayer 124 (e.g., the upper surface thereof) can be substantiallyparallel to the piezoelectric layer 116 (e.g., to the upper surfacethereof). The non-gradient portion 146 of the passivation layer 124 canhave a substantially uniform thickness. The gradient portion 148 of thepassivation layer 124 can be tapered, for example, and the upper surfaceof the gradient portion 148 of the passivation layer 124 can form agradient angle relative to upper surface of the non-gradient portion 146of the passivation layer 124. The passivation layer 124 can have adecreasing thickness moving along a direction from the main acousticallyactive region 132 (or middle area) toward the raised frame structure.The non-gradient portion 146 can be inward of the gradient portion 148of the passivation layer 124. The gradient portion 148 can at leastpartially, or completely, surround the non-gradient portion 146 (e.g.,in plan view).

The first or lower electrode 114 can have a non-gradient portion and agradient portion. The non-gradient portion of the electrode 114 (e.g.,the upper surface thereof) can be substantially parallel to thepiezoelectric layer 116 (e.g., to the upper surface thereof). Thenon-gradient portion of the electrode 114 can have a substantiallyuniform thickness. The gradient portion of the electrode 114 can betapered, and can be at an end of the electrode 114, for example. Theupper surface of the gradient portion of the electrode 114 can form agradient angle relative to upper surface of the non-gradient portion ofthe electrode 114. The electrode 114 can have a decreasing thicknessmoving along a direction from the main acoustically active region 132(or middle area) toward the raised frame structure.

The second or upper electrode 118 can have a non-gradient portion and agradient portion. The non-gradient portion of the electrode 118 (e.g.,the upper surface thereof) can be substantially parallel to thepiezoelectric layer 116 (e.g., to the upper surface thereof). Thenon-gradient portion of the electrode 118 can have a substantiallyuniform thickness. The gradient portion of the electrode 118 can betapered, and can be at an end of the electrode 118, for example. Theupper surface of the gradient portion of the electrode 118 can form agradient angle relative to upper surface of the non-gradient portion ofthe electrode 118. The electrode 118 can have a decreasing thicknessmoving along a direction from the main acoustically active region 132(or middle area) toward the raised frame structure. The first or lowerelectrode 114 can have a gradient portion on a first side of the BAWdevice, and the second or upper electrode 118 can have a gradientportion on a second side of the BAW device, such as opposite the firstside.

The active region 130 of the BAW device can be defined by the overlapbetween the non-gradient portions of the first electrode 114 and thesecond electrode 118 (e.g., and the piezoelectric layer 116 as well), asshown in FIG. 2. In some embodiments, the active region 130 of the BAWdevice can include some or all of the gradient portions of theelectrodes 114, 118. In some embodiments, the first raised frame layer120 and/or the second raised frame layer 122 can have outer gradientportion(s), as shown, for example on the right side of FIG. 2. In someembodiments, the outer gradient portion 150 of the second raised frameportion 122 can be positioned directly above a non-gradient portion ofthe electrode 118, which can be inside the active area 130 (e.g., whendefined by the overlapping non-gradient portions of the electrodes 114,118). The upper surface of the outer gradient portion(s) can form agradient angle relative to upper surface of the correspondingnon-gradient portion(s). The gradient portion(s) can have a decreasingthickness moving along a direction from the main acoustically activeregion 132 (or middle area) toward the raised frame structure.

The first raised frame layer 120 can extend inward further than thesecond raised frame layer 122. The width of the first raised frame layer120 can be larger than the width of the second raised frame layer 122.The widths of the first raised frame layer 120 and the second raisedframe layer 122 can be measured from the active boundary of the activeregion 130 (e.g., inwardly). For example, portions of the first raisedframe layer 120 and/or the second raised frame layer 122 that areoutside the active region 130 can be disregarded for determining thewidth(s) thereof (e.g., the horizontal lengths in the cross-sectionalview of FIG. 2). In some embodiments, the widths and other sizes anddimensions can be normalized or otherwise compared to the combinedthickness 154 of the first electrode 114, the piezoelectric layer 116,and the second electrode 118. The combined thickness 154 can be takenthrough the main acoustically active region 132 or middle area of theBAW device. In some embodiments, the primary resonant frequency of theBAW device can correspond to a resonant wavelength λ that can be doublethe combined thickness 154 of the piezoelectric layer 116 and the firstand second electrodes 114, 118. Accordingly, in some cases, thedimensions of the BAW device 100 can be scaled in order to resonatedifferent wavelengths and frequencies, and in some cases, the sizes anddimensions of the raised frame structure can scale with the rest of theBAW device 100.

In some embodiments, the width of the first raised frame layer 120(e.g., the combined non-gradient portion 138 and gradient portion 140)can be wider than a combined thickness 154 of the piezoelectric layer116 and the first and second electrodes 114, 118, such as about 1.1times wider, about 1.25 times wider, about 1.5 times wider, about 1.75times wider, about 2 times wider, about 2.1 time wider, about 2.2 timeswider, about 2.3 times wider, about 2.4 times wider, about 2.5 timeswider, about 2.6 times wider, about 2.7 times wider, about 2.8 timeswider, about 2.9 times wider, about 3 times wider, about 3.25 timeswider, about 3.5 times wider, about 3.75 times wider, about 4 timeswider, about 4.5 times wider, about 5 times wider, or more, or anyvalues therebetween, or any ranges between any of these values, althoughother configurations could be used. In some embodiments, the combinedthickness 154 can be smaller than shown in FIG. 2, for example. Thewidths can be taken in the active region 130, such as where the firstand second electrodes 114, 118 (e.g., the non-gradient portions thereof)overlap. In some embodiments, the non-gradient portion 138 of the firstraised frame layer 120 can be wider than a combined thickness 154 of thepiezoelectric layer 116 and the first and second electrodes 114, 118,such as about 1.1 times wider, about 1.25 times wider, about 1.5 timeswider, about 1.75 times wider, about 1.9 times wider, about 2 timeswider, about 2.1 times wider, about 2.2 times wider, about 2.3 timeswider, about 2.5 times wider, about 2.75 times wider, about 3 timeswider, about 3.5 times wider, about 4 times wider, 5 times wider, ormore, or any values therebetween, or any ranges between any of thesevalues, although other configurations could be used. In someembodiments, the combined thickness 154 can be smaller than shown inFIG. 2, for example.

In some embodiments, the non-gradient portion 138 of the first raisedframe layer 120 can be wider than the non-gradient portion 142 of thesecond raised frame layer 122 by an amount that is larger than thecombined thickness 154 of the piezoelectric layer 116 and the first andsecond electrodes 114, 118, or by an amount that is larger than athickness of the first raised frame layer 120, or by an amount that islarger than a thickness of the second raised frame layer 122, or by anamount that is larger than a combined thickness of the first and secondraised frame layers 120, 122, or by an amount that is larger thancombined thickness of the first raised frame layer 120, the secondelectrode 118, and the second raised frame layer 122. The non-gradientportion 138 of the first raised frame layer 120 can be wider than thenon-gradient portion 142 of the second raised frame layer 122, such asabout 1.25 times wider, about 1.5 times wider, about 1.75 times wider,about 2 times wider, about 2.5 times wider, about 3 times wider, about3.5 times wider, about 4 times wider, about 4.25 times wider, about 4.5times wider, about 4.75 times wider, about 4.9 times wider, about 5times wider, about 5.1 times wider, about 5.25 times wider, about 5.5times wider, about 5.75 times wider, about 6 times wider, about 6.5times wider, about 7 times wider, about 8 times wider, or more, or anyvalues therebetween, or any ranges between any of these values, althoughother configurations could be used. The non-gradient portion 138 of thefirst raised frame layer 120 can be wider than the combined width of thenon-gradient portion 142 and the gradient portion 144 of the secondraised frame layer 122, such as about 1.05 times wider, about 1.1 timeswider, about 1.15 times wider, about 1.2 times wider, about 1.25 timeswider, about 1.3 times wider, about 1.35 times wider, about 1.4 timeswider, about 1.45 times wider, about 1.5 times wider, about 1.6 timeswider, about 1.75 times wider, about 2 times wider, about 2.5 timeswider, about 3 times wider, or more, or any values therebetween, or anyranges between any of these values, although other configurations couldbe used.

The combined width of non-gradient portion 138 and the gradient portion140 of the first raised frame layer 120 can be wider than the combinedwidth of the non-gradient portion 142 and the gradient portion 144 ofthe second raised frame layer 122, such as about 1.05 times wider, about1.1 times wider, about 1.2 times wider, about 1.25 times wider, about1.3 times wider, about 1.35 times wider, about 1.4 times wider, about1.45 times wider, about 1.5 times wider, about 1.55 times wider, about1.6 times wider, about 1.7 times wider, about 1.8 times wider, about 2times wider, about 2.5 times wider, about 3 times wider, about 4 timeswider, or more, or any values therebetween, or any ranges between any ofthese values, although other configurations could be used.

The non-gradient portion 138 of the first raised frame layer 120 canextend inwardly past the non-gradient portion 142 of the second raisedframe layer 122 by a distance (e.g., the combined distances 144 and 152in FIG. 2) that is larger than the thickness of the first raised framelayer 120, or larger than the thickness of the second raised frame layer122, or larger than a combined thickness of the first raised frame layer120 and the second raised frame layer 122, or larger than a combinedthickness of the first raised frame layer 120, the second electrode 118,and the second raised frame layer 122. In some embodiments, thenon-gradient portion 138 of the first raised frame layer 120 can extendinwardly past the non-gradient portion 142 of the second raised framelayer 122 by a distance (e.g., the combined distances 144 and 152 inFIG. 2) that is larger than the combined thickness 154 of thepiezoelectric layer 116 and the first and second electrodes 114, 118,such as about 1.05 times larger, about 1.1 times larger, about 1.25times larger, about 1.4 times larger, about 1.45 times larger, about 1.5times larger, about 1.55 times larger, about 1.6 times larger, about1.65 times larger, about 1.7 times larger, about 1.75 times larger,about 1.8 times larger, about 1.85 times larger, about 1.9 times larger,about 2 times larger, about 2.25 times larger, about 2.5 times larger,or about 3 times larger, or more, or any values therebetween, or anyranges between any of these values, although other configurations couldbe used.

The non-gradient portion 138 of the first raised frame layer 120 canextend inwardly past the gradient portion 144 of the second raised framelayer 122 by a distance (e.g., the distance 152 in FIG. 2) that islarger than the thickness of the first raised frame layer 120, or largerthan the thickness of the second raised frame layer 122, or larger thana combined thickness of the first raised frame layer 120 and the secondraised frame layer 122, or larger than a combined thickness of the firstraised frame layer 120, the second electrode 118, and the second raisedframe layer 122. In some embodiments, the non-gradient portion 138 ofthe first raised frame layer 120 can extend inwardly past the gradientportion 144 of the second raised frame layer 122 by a distance (e.g.,the distance 152 in FIG. 2) that is a percentage of the combinedthickness 154 of the piezoelectric layer 116 and the first and secondelectrodes 114, 118, and the percentage can be about 10%, about 20%,about 25%, about 30%, about 35%, about 40%, about 45%, about 50%, about55%, about 60%, about 70%, about 75%, about 80%, about 90%, about 100%,or more, or any ranges between any of these values, although otherconfigurations could be used.

The gradient portion 140 of the first raised frame layer 120 can extendinwardly past the gradient portion 144 of the second raised frame layer122 by a distance (e.g., the combined distances 140 and 152 in FIG. 2)that is larger than the thickness of the first raised frame layer 120,or larger than the thickness of the second raised frame layer 122, orlarger than a combined thickness of the first raised frame layer 120 andthe second raised frame layer 122, or larger than a combined thicknessof the first raised frame layer 120, the second electrode 118, and thesecond raised frame layer 122. In some embodiments, the gradient portion140 of the first raised frame layer 120 can extend inwardly past thegradient portion 144 of the second raised frame layer 122 by a distance(e.g., the combined distances 140 and 152 in FIG. 2) that is apercentage of the combined thickness 154 of the piezoelectric layer 116and the first and second electrodes 114, 118, and the percentage can beabout 10%, about 25%, about 50%, about 55%, about 60%, about 65%, about70%, about 75%, about 80%, about 85%, about 90%, about 100%, about 125%,about 150%, or more, or any ranges between any of these values, althoughother configurations could be used.

The raised frame structure can have an outer non-gradient portion, whichcan be associated with the non-gradient portion 142 of the second raisedframe layer 122, and which can have a substantially uniform overallthickness. The raised frame structure can have an outer gradientportion, which can be associated with the gradient portion 144 of thesecond raised frame layer 122, and which can have a tapered overallthickness. The raised frame structure can have an inner non-gradientportion 152, which can be associated with the non-gradient portion 138of the first raised frame layer 120 that extends inward beyond thesecond raised frame layer 122, and which can have a substantiallyuniform overall thickness. The raised frame structure can have an innergradient portion, which can be associated with the gradient portion 140of the first raised frame layer 120, and which can have a taperedoverall thickness. In some embodiments, the outer non-gradient portion(e.g., 142) can have a width that is substantially the same as the widthof the inner non-gradient portion (e.g., 152). In some embodiments, thewidths of the outer non-gradient portion (e.g., 142) and the innernon-gradient portion (e.g., 152) can vary by about 25% or less, by about20%, by about 15% or less, by about 10% or less, by about 5% or less, orby about 0%.

In some cases, the first raised frame 120 designs disclosed herein canmore effectively reduce an effective electromechanical couplingcoefficient (k²) of the raised frame domain or region 134 of the BAWdevice 100 relative to other BAW devices, such as the BAW devicedescribed in connection with FIG. 4. This can reduce excitation strengthof a raised frame spurious mode. Moreover, the first raised frame layer120 can be configured to contribute to move the frequency of the raisedframe mode relatively far away from the main resonant frequency of theBAW device 100, which can result in little or no Gamma loss.

FIG. 3 is a cross-sectional view of an example BAW device 101 that doesnot include a raised frame structure. The BAW device 101 of FIG. 3 caninclude a substrate 110, cavity 112, first or lower electrode 114,piezoelectric layer 116, second or upper electrode 118, and passivationlayer 124, which can be similar to the corresponding components of theBAW device 100 of FIG. 2.

FIG. 4 is a cross-sectional view of an example BAW device 103 that has araised frame structure that is different from the embodiment illustratedin FIG. 2. The BAW device 103 of FIG. 4 can include a substrate 110,cavity 112, first or lower electrode 114, piezoelectric layer 116,second or upper electrode 118, and passivation layer 124, which can besimilar to the corresponding components of the BAW device 100 of FIG. 2.The BAW device 103 can have a raised frame structure with a first raisedframe structure 120 and a second raised frame structure 122, which canbe similar to the corresponding components in the BAW device 100 of FIG.2, except that the second raised frame 122 of the BAW device 103 canextend beyond the first raised frame 120 (e.g., inwardly).

FIG. 5 is a partial cross-sectional view of a BAW device 101, which canbe similar to the BAW device 101 of FIG. 3. The example BAW device 101has a lower electrode 114 with a thickness of 0.34 microns, apiezoelectric layer 116 with a thickness of 0.96 microns, and a secondor upper electrode 118 with a thickness of 0.37 microns, with a combinedthickness of 167 microns. The BAW device 101 can have a passivationlayer 124. The BAW device 101 does not have a raised frame structure.

FIG. 6 is a graph that shows results for simulated admittance for theBAW device 101 of FIG. 5. FIG. 6 shows that the BAW device 101 has aresonant frequency of 1.813 GHz and an anti-resonant frequency at 1.863GHz.

FIG. 7 is a graph that shows results for simulated conductance for theBAW device 101 of FIG. 5. FIG. 7 that the BAW device 101 has goodperformance below the resonant frequency, but significant degradationabove the resonant frequency.

FIG. 8 is a partial cross-sectional view of an example BAW device 103,which can be similar to the BAW device 103 of FIG. 4. The example BAWdevice 103 has a lower electrode 114 with a thickness of 0.34 microns, apiezoelectric layer 116 with a thickness of 0.96 microns, and a secondor upper electrode 118 with a thickness of 0.37 microns, with a combinedthickness of 167 microns. The BAW device 103 can have a passivationlayer 124. The BAW device 103 has a raised frame structure with a firstraised frame layer 120 and a second raised frame layer 122. The firstraised frame layer 120 has a non-gradient portion 138 with a width of1.4 microns and a gradient portion 140 with a width of about 0.4microns. The first raised frame layer 120 can have a thickness of 0.14microns (at the non-gradient portion 138). The second raised frame layer122 has a non-gradient portion 142 with a width of about 2.5 microns anda gradient portion 144 with a width of about 1.6 microns. The secondraised frame layer 122 can have a thickness of 0.18 microns (at thenon-gradient portion 142). The non-gradient portion 142 of the secondraised frame layer 122 can extend inwardly past the first raised framelayer 120 by a distance 152, which can be 0.7 microns.

FIG. 9 is a graph that shows results for simulated admittance for theBAW device 103 of FIG. 8. FIG. 9 shows that the BAW device 103 has aresonant frequency of 1.813 GHz and an anti-resonant frequency at 1.863GHz.

FIG. 10 is a graph that shows results for simulated conductance for theBAW device 103 of FIG. 8. FIG. 10 shows that the BAW device 103 hasimproved performance above the resonant frequency, but significantdegradation below the resonant frequency, as compared to the BAW device101 with no raised frame structure. For example, the raised framestructure can produce a relatively large spurious mode 156, which can bereferred to as a raised frame mode. The spurious mode 156 can be athickness extension mode.

FIG. 11 is a partial cross-sectional view of an example BAW device 100,which can be similar to the BAW device 100 of FIG. 2. The example BAWdevice 100 has a lower electrode 114 with a thickness of 0.34 microns, apiezoelectric layer 116 with a thickness of 0.96 microns, and a secondor upper electrode 118 with a thickness of 0.37 microns, with a combinedthickness of 167 microns. The BAW device 100 can have a passivationlayer 124. The BAW device 100 has a raised frame structure with a firstraised frame layer 120 and a second raised frame layer 122. The firstraised frame layer 120 has a non-gradient portion 138 with a width of3.5 microns and a gradient portion 140 with a width of about 0.5microns. The first raised frame layer 120 can have a thickness of 0.18microns (at the non-gradient portion 138). The second raised frame layer122 has a non-gradient portion 142 with a width of about 0.7 microns anda gradient portion 144 with a width of about 2.1 microns. The secondraised frame layer 122 can have a thickness of 0.18 microns (at thenon-gradient portion 142). The non-gradient portion 138 of the firstraised frame layer 120 can extend inwardly past the second raised framelayer 122 by a distance 152, which can be 0.7 microns.

FIG. 12 is a graph that shows results for simulated admittance for theBAW device 100 of FIG. 11. FIG. 12 shows that the BAW device 100 has aresonant frequency of 1.813 GHz and an anti-resonant frequency at 1.863GHz.

FIG. 13 is a graph that shows results for simulated conductance for theBAW device 100 of FIG. 11. FIG. 13 shows that the BAW device 100 hasimproved performance above the resonant frequency, as compared to theBAW device 101 with no raised frame structure, and that also hasimproved performance below the resonant frequency as compared to the BAWdevice 103 of FIG. 8. For example, the spurious mode 156, in FIG. 10 canbe significantly reduced in FIG. 13.

In some embodiments, the second raised frame 122 can be omitted. FIG. 14is a partial cross-sectional view of an example BAW device 105, whichcan be similar to the BAW device 100 of FIG. 4, except that the secondraised frame layer 122 is omitted. The example BAW device 105 has alower electrode 114 with a thickness of 0.34 microns, a piezoelectriclayer 116 with a thickness of 0.96 microns, and a second or upperelectrode 118 with a thickness of 0.37 microns, with a combinedthickness of 167 microns. The BAW device 100 can have a passivationlayer 124. The BAW device 100 has a raised frame structure with a raisedframe layer 120. The raised frame layer 120 has a non-gradient portion138 with a width of 1.5 microns and a gradient portion 140 with a widthof about 0.4 microns. The raised frame layer 120 can have a thickness of0.14 microns (at the non-gradient portion 138).

FIG. 15 is a graph that shows results for simulated admittance for theBAW device 105 of FIG. 14. FIG. 15 shows that the BAW device 105 has aresonant frequency of 1.813 GHz and an anti-resonant frequency at 1.863GHz.

FIG. 16 is a graph that shows results for simulated conductance for theBAW device 105 of FIG. 14. FIG. 16 shows that the BAW device 105 hasimproved performance above the resonant frequency, as compared to theBAW device 101 with no raised frame structure, and that also hasimproved performance below the resonant frequency as compared to the BAWdevice 103 of FIG. 8. For example, the spurious mode 156, in FIG. 10 canbe significantly reduced in FIG. 16. The performance below the resonantfrequency can be better for the BAW device 100 of FIG. 11 than for theBAW device 105 of FIG. 14.

FIG. 17 is a graph that shows the results from FIGS. 6, 9, 12, and 15combined into a single graph, for ease of comparison.

FIG. 18 is a graph that shows the results from FIGS. 7, 10, 13, and 16combined into a single graph, for ease of comparison.

FIG. 19 is a graph that shows results for simulated filter response fora ladder filter that uses the BAW device 101 of FIG. 5, such as with noraised frame structure. FIG. 20 is a graph that shows results forsimulated filter response for a ladder filter that uses the BAW device103 of FIG. 8, such as with a raised frame structure where the secondraised frame layer 122 extends further inward than the first raisedframe layer 120. The filter response of FIG. 20 can have improvedperformance, as compared to the filter response of FIG. 19, but thefilter response of FIG. 20 shows degradation at locations 158, which canbe from thickness extension leakage from the spurious mode, which can beproduced by the raised frame structure of FIG. 8. FIG. 21 is a graphthat shows results for simulated filter response for a ladder filterthat uses the BAW device 100 of FIG. 11, such as with a raised framestructure where the first raised frame layer 120 extends further inwardthan the second raised frame layer 122. The degradation discussed inconnection with FIG. 20 can be reduced or eliminated in the filterresponse of FIG. 21, indicating that the raised frame structure of FIG.11 can provide better filter performance, such as by suppressing thespurious mode. FIG. 22 is a graph that shows results for simulatedfilter response for a ladder filter that uses the BAW device 100 of FIG.14, such as with a raised frame structure having a raised frame layer120, and wherein the raised frame layer 122 is omitted. The degradationdiscussed in connection with FIG. 20 can be reduced or eliminated in thefilter response of FIG. 22, indicating that the raised frame structureof FIG. 14 can provide better filter performance, such as by suppressingthe spurious mode. FIG. 23 is a graph that shows results for simulatedfilter response for a ladder filter that uses parallel resonators withthe BAW device 100 of FIG. 11, such as with a raised frame structurewhere the first raised frame layer 120 extends further inward than thesecond raised frame layer 122, and series resonators with the BAW device103 of FIG. 8. The degradation discussed in connection with FIG. 20 canbe reduced or eliminated in the filter response of FIG. 23, indicatingthat the raised frame structure of FIGS. 8 and 11 (or FIGS. 2 and 4) canbe combined to provide better improved filter performance, such as bysuppressing the spurious mode. FIG. 24 is a graph that shows the resultsfrom FIG. 19-23 combined into a single graph, for ease of comparison.

FIG. 25 is a graph that shows results for simulated conductance for theBAW device 103 of FIG. 8, but for multiple widths for the non-gradientportion 138 of the first raised frame layer 120. FIG. 25 shows that asthe width of the non-gradient portion 138 of the first raised framelayer 120 is reduced (e.g., from 1.8 microns to 1.4 microns) in the BAWdevice 103, the spurious mode can shift to a higher frequency (e.g.,from about 1.68 GHz to about 1.7 GHz). FIG. 25 also shows thatincreasing the width of the non-gradient portion 138 of the first raisedframe layer 120 (e.g., from 1.8 microns to 2.2 microns) can cause thespurious mode to shift to a lower frequency (e.g., from about 1.68 GHzto about 1.67 GHz). In some cases, shifting the spurious mode to a lowerfrequency can result in a next period spurious mode 160 at a higherfrequency than the spurious mode that was shifted to a lower frequency.In some cases increasing the width of the first raised frame layer 120and/or reducing the width of the second raised frame layer 122 (e.g., sothat the first raised frame layer 120 extends further inward than thesecond raised frame layer 122), as shown in FIG. 11 can result in betterperformance (e.g., as shown in FIG. 13), as compared to merely adjustingthe width of the first raised frame layer 120 (e.g., as shown in FIG.25).

FIG. 26 is a graph that shows results for simulated conductance for theBAW device 103 of FIG. 8, but for multiple thicknesses 162 for thenon-gradient portion 142 of the second raised frame layer 122. FIG. 26shows that as the thickness 162 of the second raised frame layer 122 isreduced (e.g., from 0.14 microns to 0.1 microns) in the BAW device 103,the spurious mode can shift to a higher frequency (e.g., from about 1.68GHz to about 1.72 GHz). FIG. 26 also shows that increasing the thicknessof the second raised frame layer 122 (e.g., from 0.18 microns to 0.22microns) can cause the spurious mode to shift to a lower frequency(e.g., from about 1.68 GHz to about 1.66 GHz). In some cases, shiftingthe spurious mode to a lower frequency can result in a next periodspurious mode 160 at a higher frequency than the spurious mode that wasshifted to a lower frequency. In some cases increasing the width of thefirst raised frame layer 120 and/or reducing the width of the secondraised frame layer 122 (e.g., so that the first raised frame layer 120extends further inward than the second raised frame layer 122), as shownin FIG. 11 can result in better performance (e.g., as shown in FIG. 13),as compared to merely adjusting the thickness of the second raised framelayer 122 (e.g., as shown in FIG. 26).

FIG. 27 is a graph that shows results for simulated conductance for theBAW device 103 of FIG. 8, but for multiple thicknesses 164 for thenon-gradient portion 138 of the first raised frame layer 120. FIG. 27shows that as the thickness 164 of the first raised frame layer 120 isreduced (e.g., from 0.14 microns to 0.1 microns) in the BAW device 103,the spurious mode can shift to a higher frequency (e.g., from about 1.68GHz to about 1.72 GHz). FIG. 27 also shows that increasing the thickness164 of the non-gradient portion 138 of the first raised frame layer 120(e.g., from 0.14 microns to 0.18 microns) can cause the spurious mode toshift to a lower frequency (e.g., from about 1.68 GHz to about 1.63GHz), and/or can partially suppress the spurious mode, although in FIG.27 the spurious mode is still above -35 dB. In some cases, increasingthe width of the first raised frame layer 120 and/or reducing the widthof the second raised frame layer 122 (e.g., so that the first raisedframe layer 120 extends further inward than the second raised framelayer 122), as shown in FIG. 11 can result in better performance (e.g.,as shown in FIG. 13), as compared to merely adjusting the thickness ofthe first raised frame layer 120 (e.g., as shown in FIG. 27).

FIG. 28 is a graph that shows results for simulated conductance for theBAW device 103 of FIG. 8, but for multiple widths for the non-gradientportion 142 of the second raised frame layer 122. FIG. 28 shows that asthe width of the second raised frame layer 122 is reduced (e.g., withportion 152 reducing from 0.45 microns to 0.2 microns) in the BAW device103, the spurious mode can shift to a higher frequency (e.g., from about1.685 GHz to about 1.7 GHz). FIG. 28 also shows that increasing thewidth of the second raised frame layer 122 (e.g., with the portion 152increasing from 0.45 microns to 0.7 microns) can cause the spurious modeto shift to a lower frequency (e.g., from about 1.685 GHz to about 1.68GHz). In some cases, shifting the spurious mode to a lower frequency canresult in a next period spurious mode 160 at a higher frequency than thespurious mode that was shifted to a lower frequency. In some casesincreasing the width of the first raised frame layer 120 and/or reducingthe width of the second raised frame layer 122 (e.g., so that the firstraised frame layer 120 extends further inward than the second raisedframe layer 122), as shown in FIG. 11 can result in better performance(e.g., as shown in FIG. 13), as compared to merely adjusting the widthof the second raised frame layer 122 (e.g., as shown in FIG. 28).

FIG. 29 is a graph that shows results for simulated conductance for theBAW device 100 of FIG. 11, but for multiple thicknesses 164 for thenon-gradient portion 138 of the first raised frame layer 120. FIG. 29shows that as the thickness 164 of the first raised frame layer 120increases (e.g., from 0.1 microns to 0.14 microns to 0.18 microns) inthe BAW device 100, the spurious mode can be suppressed.

FIG. 30 is a graph that shows results for simulated conductance for theBAW device 105 of FIG. 14, but for multiple thicknesses 164 for thenon-gradient portion 138 of the first raised frame layer 120. FIG. 30shows that as the thickness 164 of the first raised frame layer 120increases (e.g., from 0.1 microns to 0.14 microns to 0.18 microns to0.22 microns) in the BAW device 105, the performance can be improved.For a thickness 164 of 0.1 microns, the BAW can have significantdegradation, such as above the resonant frequency. Accordingly, FIG. 30shows that for BAW devices with a relatively thin low acoustic impedancelayer (e.g., layer 120), the inclusion of a relatively high acousticimpedance layer (e.g., layer 122) can significantly improve the responseof the BAW device. For BAW devices with a relatively thick acousticimpedance layer (e.g., layer 120), the BAW device can have goodperformance parameters, even without the second raised frame layer 122.

In some embodiments, the first raised frame layer 120 can have athickness 164 of about 0.02 times, about 0.04 times, about 0.05 times,about 0.06 times, about 0.07 times, about 0.08 times, about 0.09 times,about 0.1 times, about 0.11 times, about 0.12 times, about 0.13 times,about 0.14 times, about 0.15 times, about 0.16 times, about 0.18 times,about 0.2 times, about 0.25 times, or about 0.3 times, or about 0.4times the combined thickness 154 of the first electrode 114, thepiezoelectric layer 116, and the second electrode 118, or any valuestherebetween, or any ranges bounded by any of these values. By way ofselect examples, the thickness 164 of the first raised frame layer 120can be between about 0.04 times and about 0.2 times the combinedthickness 154, or between about 0.06 times and about 0.15 times thecombined thickness 154, or between about 0.075 times and about 0.125times the combined thickness 154, although various designs can be used.The thickness of the first raised frame layer 120 can be taken at thenon-gradient portion 138. In some embodiments, the second raised framelayer 122 can be omitted, and in other embodiments, the second raisedframe layer 122 can be included.

In some embodiments, the second raised frame layer 122 can have athickness 162 of about 0.02 times, about 0.04 times, about 0.05 times,about 0.06 times, about 0.07 times, about 0.08 times, about 0.09 times,about 0.1 times, about 0.11 times, about 0.12 times, about 0.13 times,about 0.14 times, about 0.15 times, about 0.16 times, about 0.18 times,about 0.2 times, about 0.25 times, or about 0.3 times, or about 0.4times the combined thickness 154 of the first electrode 114, thepiezoelectric layer 116, and the second electrode 118, or any valuestherebetween, or any ranges bounded by any of these values. By way ofselect examples, the thickness 162 of the second raised frame layer 122can be between about 0.04 times and about 0.2 times the combinedthickness 154, or between about 0.06 times and about 0.15 times thecombined thickness 154, or between about 0.075 times and about 0.125times the combined thickness 154, although various designs can be used.The thickness of the second raised frame layer 122 can be taken at thenon-gradient portion 142.

A gradient portion of the raised frame structure or components thereofcan have a gradient angle 166 with respect to a horizontal direction inthe illustrated embodiments. FIG. 31 shows the gradient angle 166. Theangle 166 can be with respect to an underlying layer (e.g., apiezoelectric layer). The gradient portion of the first raised framelayer 120 can have an upper surface that is angled (e.g., downward ortowards the piezoelectric layer 116 or lower electrode 114) by an angle166. The gradient angle 166 of the first raised frame layer 120 canaffect the layers above the first raised frame layer 120. The upperelectrode 118, the second raised frame layer 122, and/or the passivationlayer 124 can also have the gradient angle 166. The gradient angle 150can be less than 90° or less than about 40°, in some embodiments. Insome cases, the taper angle can be about 5°, about 10°, about 15°, about20°, about 30°, about 45°, about 60°, about 75°, or any valuestherebetween, or any ranges between any of these values. For example, insome instances, the angle 166 can be in a range from about 10° to about30° for a gradient portion of a raised frame layer in a gradient region,or for other associated layers. In some embodiments, differentcomponents can have different gradient angles 166. For example, as canbe seen in FIG. 2, the gradient angle of the first raised frame layer120 can be higher than the gradient angle for the second raised framelayer 120.

The BAW device can be a film bulk acoustic wave resonator (FBAR). Acavity 112 can be included, such as below the first electrode 114. Thecavity 112 can be filled with air, in some implementations. The cavity112 can be defined by the geometry of the first electrode 114 and thesubstrate 110. Although the BAW devices 100 illustrated in FIG. 2-4 areFBAR devices, any suitable principles and advantages discussed hereincan be applied to a solidly mounted resonator (SMR).

FIG. 32 is a cross-sectional view of an example embodiment of a BAWdevice 107, which can be similar to the BAW device 100 of FIG. 2, exceptthat the BAW device 100 is an SMR instead of an FBAR. In the BAW device107 of FIG. 32, a solid acoustic mirror can be disposed between thefirst electrode 114 and a silicon substrate 110. The illustratedacoustic mirror includes acoustic Bragg reflectors. The illustratedacoustic Bragg reflectors include alternating low impedance layers 168and high impedance layers 170. As an example, the Bragg reflectors caninclude alternating silicon dioxide layers as low impedance layers 168and tungsten layers as high impedance layers 170, although othersuitable materials could be used. The raised frame layer structure ofthe embodiment of FIG. 32 can have similar features and functionality tothe raised frame structure in the embodiment of FIG. 2, or any otherembodiments disclosed herein. The raised frame layer 120 in theembodiment of FIG. 32 can have similar features and functionality to thefirst raised frame layer 120 in the embodiment of FIG. 2. The firstraised frame layer 120 in the embodiment of FIG. 32 can be wider thanthe second raised frame layer 122, as described in connection with FIG.2.

Many other variations are possible. For example, the first raised framelayer 120 can be between the second electrode 118 and the piezoelectriclayer 116, as shown in FIG. 2, for example. Alternatively, the firstraised frame layer 120 can be between the first electrode 114 and thepiezoelectric layer 116. The disclosure relating to the widths andthickness and other parameters of the first raised frame layer 120 canapply when the first raised frame layer 120 is between the lowerelectrode 114 and the piezoelectric layer 116. In some embodiments, thesecond raised frame layer 122 can be omitted. The disclosure relating tothe widths and thickness and other parameters of the first raised framelayer 120 can apply when the second raised frame layer is omitted.

The various features of the BAW devices disclosed herein can becombined. For example, any of the BAW devices disclosed herein can be anSMR instead of an FBAR (e.g., as shown in FIG. 32). Any of the BAWdevices disclosed herein can have the first raised frame layer 120disposed between the lower electrode 114 and the piezoelectric layer116. Any of the BAW devices can omit the second raised frame layer 122(e.g., as shown in FIG. 14). Any of the BAW devices can omit therecessed frame region 136 or can omit the passivation layer 124. A BAWdevice 100 can include any combination of these features.

The BAW resonators disclosed herein can be implemented in acoustic wavefilters. In certain applications, the acoustic wave filters can be bandpass filters arranged to pass a radio frequency band and attenuatefrequencies outside of the radio frequency band. Two or more acousticwave filters can be coupled together at a common node and arranged as amultiplexer, such as a duplexer.

FIG. 33 is a schematic diagram of an example of an acoustic wave ladderfilter 220. The acoustic wave ladder filter 220 can be a transmit filteror a receive filter. The acoustic wave ladder filter 220 can be a bandpass filter arranged to filter a radio frequency signal. The acousticwave filter 220 can include series resonators 222 (R1, R3, R5, R7, andR9) and shunt resonators 224 (R2, R4, R6, and R8) coupled between aradio frequency input/output port RFI/O and an antenna port ANT. Theradio frequency input/output port RFI/O can be a transmit port in atransmit filter or a receive port in a receive filter. The resonators222, 224 can be positioned between any two RF input/output ports. One ormore of the illustrated acoustic wave resonators 222, 224 can be a bulkacoustic wave resonator in accordance with any suitable principles andadvantages discussed herein. An acoustic wave ladder filter can includeany suitable number of series resonators and any suitable number ofshunt resonators. The shunt resonators 224 can be coupled in parallelbetween the series resonators 222 and ground, and can be called parallelresonators in some cases.

Embodiments disclosed herein relate to utilizing various types of BAWdevices in a filter to achieve higher performance than a filter thatimplement a single type of BAW device. In a band pass filter, the seriesresonators 222 (R1, R3, R5, R7, and R9) can include at least one firsttype of BAW resonator that includes a first raised frame structure andthe shunt resonators 224 (R2, R4, R6, and R8) can include at least onesecond type of BAW resonator that includes a second raised framestructure that is different from the first raised frame structure. Forexample, the series resonators 222 (R1, R3, R5, R7, and R9) can includeBAW resonators 100 according to the design disclosed in connection withFIG. 2, where the first raised frame layer 120 extends inward beyond thesecond raised frame layer 122. The shunt resonators 224 (R2, R4, R6, andR8) can include BAW resonators 103 according to the design disclosed inconnection with FIG. 4, where the second raised frame layer 122 extendsinward beyond the first raised frame layer 120. This arrangement isdiscussed and the filter response is shown in connection with FIG. 23.The shunt resonators 224 (R2, R4, R6, and R8) can use other BAWresonators disclosed herein or other BAW designs as well, in someembodiments.

In a band rejection filter, the shunt resonators 224 (R2, R4, R6, andR8) can include at least one first type BAW resonator that includes afirst raised frame structure and the series resonators 222 (R1, R3, R5,R7, and R9) can include at least one second type BAW resonator thatinclude a second raised frame structure. The second raised framedstructure is different than the first raised frame structure. Forexample, the series resonators 222 (R1, R3, R5, R7, and R9) can includeBAW resonators 103 according to the design disclosed in connection withFIG. 4, where the second raised frame layer 122 extends inward beyondthe first raised frame layer 120. The shunt resonators 224 (R2, R4, R6,and R8) can include BAW resonators 100 according to the design disclosedin connection with FIG. 2, where the first raised frame layer 120extends inward beyond the second raised frame layer 122. The seriesresonators 222 (R1, R3, R5, R7, and R9) can use other BAW resonatorsdisclosed herein or other BAW designs as well, in some embodiments.

The first raised framed structure can be different from the secondraised frame structure. The series bulk acoustic wave resonator(s) canhave a first resonant frequency and/or a first anti-resonant frequency.The shunt bulk acoustic wave resonator(s) can have a second resonantfrequency and/or a second anti-resonant frequency. In some embodiments,the second raised frame structure contributes to the series bulkacoustic wave resonator having a higher quality factor below the secondresonant frequency than the shunt bulk acoustic wave resonator has belowthe first resonant frequency.

An acoustic wave filter can be arranged in any other suitable filtertopology, such as a lattice topology or a hybrid ladder and latticetopology. A bulk acoustic wave resonator in accordance with any suitableprinciples and advantages disclosed herein can be implemented in a bandpass filter. In some other applications, a bulk acoustic wave resonatorin accordance with any suitable principles and advantages disclosedherein can be implemented in a band stop or band rejection filter.

FIG. 34 is a schematic diagram of an example of a duplexer 230. Theduplexer 230 can include a transmit filter 231 and a receive filter 232coupled to each other at an antenna node ANT. A shunt inductor L1 can beconnected to the antenna node ANT. The transmit filter 231 and thereceive filter 232 can both be acoustic wave ladder filters in theduplexer 230.

The transmit filter 131 can filter a radio frequency signal and providea filtered radio frequency signal to the antenna node ANT. A seriesinductor L2 can be coupled between a transmit input node TX and theacoustic wave resonators of the transmit filter 131. The illustratedtransmit filter 131 can include acoustic wave resonators T01 to T09. Oneor more of these resonators can be bulk acoustic wave resonator inaccordance with any suitable principles and advantages disclosed herein.The illustrated receive filter can include acoustic wave resonators R01to R09. One or more of these resonators can be a bulk acoustic waveresonator in accordance with any suitable principles and advantagesdisclosed herein. The receive filter can filter a radio frequency signalreceived at the antenna node ANT. A series inductor L3 can be coupledbetween the resonator and a receive output node RX. The receive outputnode RX of the receive filter provides a radio frequency receive signal.

FIG. 35 is a schematic diagram of a multiplexer 235 that includes anacoustic wave filter according to an embodiment. The multiplexer 235 caninclude a plurality of filters 236A to 236N coupled together at a commonnode COM. The plurality of filters can include any suitable number offilters including, for example, 3 filters, 4 filters, 5 filters, 6filters, 7 filters, 8 filters, or more filters. Some or all of theplurality of acoustic wave filters can be acoustic wave filters. Each ofthe illustrated filters 236A, 236B, and 236N can be coupled between thecommon node COM and a respective input/output node RFI/O1, RFI/O2, andRFI/ON.

In some instances, all filters of the multiplexer 235 can be receivefilters. According to some other instances, all filters of themultiplexer 235 can be transmit filters. In various applications, themultiplexer 235 can include one or more transmit filters and one or morereceive filters. Accordingly, the multiplexer 235 can include anysuitable number of transmit filters and any suitable number of receivefilters. Each of the illustrated filters can be band pass filters havingdifferent respective pass bands.

The multiplexer 235 is illustrated with hard multiplexing with thefilters 236A to 236N having fixed connections to the common node COM. Insome other applications, one or more of the filters of a multiplexer canbe electrically connected to the common node by a respective switch. Anyof such filters can include a bulk acoustic wave resonator according toany suitable principles and advantages disclosed herein.

A first filter 236A can be an acoustic wave filter having a first passband and arranged to filter a radio frequency signal. The first filter236A can include one or more bulk acoustic wave resonators according toany suitable principles and advantages disclosed herein. A second filter236B has a second pass band. In some embodiments, a raised framestructure of one or more bulk acoustic wave resonators of the firstfilter 236A can move a raised frame mode of the one or more bulkacoustic wave resonators away from the second passband. This canincrease a reflection coefficient (Gamma) of the first filter 236A inthe pass band of the second filter 236B. The raised frame structure ofthe bulk acoustic wave resonator of the first filter 236A can also movethe raised frame mode away from the passband of one or more otherfilters of the multiplexer 235.

In certain instances, the common node COM of the multiplexer 235 can bearranged to receive a carrier aggregation signal including at least afirst carrier associated with the first passband of the first filter236A and a second carrier associated with the second passband of thesecond filter 236B. A multi-layer raised frame structure of a bulkacoustic wave resonator of the first filter 236A can maintain and/orincrease a reflection coefficient of the first filter 236A in the secondpassband of the second filter 236B that is associated with the secondcarrier of the carrier aggregation signal.

The filters 236B to 236N of the multiplexer 235 can include one or moreacoustic wave filters, one or more acoustic wave filters that include atleast one bulk acoustic wave resonator with a raised frame structure,one or more LC filters, one or more hybrid acoustic wave LC filters, orany suitable combination thereof.

The raised frame bulk acoustic wave resonators disclosed herein can beimplemented in a variety of packaged modules. Some example packagedmodules will now be discussed in which any suitable principles andadvantages of the bulk acoustic wave devices disclosed herein can beimplemented. The example packaged modules can include a package thatencloses the illustrated circuit elements. The illustrated circuitelements can be disposed on a common packaging substrate. The packagingsubstrate can be a laminate substrate, for example. FIGS. 12, 13A, 13B,and 14 are schematic block diagrams of illustrative packaged modulesaccording to certain embodiments. Certain example packaged modules caninclude one or more radio frequency amplifiers, such as one or morepower amplifiers and/or one or more low noise amplifiers. Any suitablecombination of features of these modules can be implemented with eachother. While duplexers are illustrated in the example packaged modulesof FIGS. 12, 13A, and 14, any other suitable multiplexer that includes aplurality of acoustic wave filters coupled to a common node can beimplemented instead of one or more duplexers. For example, a quadplexercan be implemented in certain applications. Alternatively oradditionally, one or more filters of a packaged module can be arrangedas a transmit filter or a receive filter that is not included in amultiplexer.

FIG. 36 is a schematic block diagram of an example module 240 thatincludes duplexers 241A to 241N and an antenna switch 242. One or morefilters of the duplexers 241A to 241N can include any suitable number ofmulti-layer raised frame bulk acoustic wave resonators in accordancewith any suitable principles and advantages discussed herein. Anysuitable number of duplexers 241A to 241N can be implemented. Theantenna switch 242 can have a number of throws corresponding to thenumber of duplexers 241A to 241N. The antenna switch 242 canelectrically couple a selected duplexer to an antenna port of the module240.

FIG. 37A is a schematic block diagram of an example module 250 thatincludes a power amplifier 252, a radio frequency switch 254, andduplexers 241A to 241N in accordance with one or more embodiments. Thepower amplifier 252 can amplify a radio frequency signal. The radiofrequency switch 254 can be a multi-throw radio frequency switch. Theradio frequency switch 254 can electrically couple an output of thepower amplifier 252 to a selected transmit filter of the duplexers 241Ato 241N. One or more filters of the duplexers 241A to 241N can includeany suitable number of raised frame bulk acoustic wave resonators inaccordance with any suitable principles and advantages discussed herein.Any suitable number of duplexers 241A to 241N can be implemented.

FIG. 37B is a schematic block diagram of an example module 255 thatincludes filters 256A to 256N, a radio frequency switch 257, and a lownoise amplifier 258 according to one or more embodiments. One or morefilters of the filters 256A to 256N can include any suitable number ofraised frame bulk acoustic wave resonators in accordance with anysuitable principles and advantages disclosed herein. Any suitable numberof filters 256A to 256N can be implemented. The illustrated filters 256Ato 256N can be receive filters. In some embodiments (not illustrated),one or more of the filters 256A to 256N can be included in a multiplexerthat also includes a transmit filter. The radio frequency switch 257 canbe a multi-throw radio frequency switch. The radio frequency switch 257can electrically couple an output of a selected filter of filters 256Ato 256N to the low noise amplifier 257. In some embodiments (notillustrated), a plurality of low noise amplifiers can be implemented.The module 255 can include diversity receive features in certainapplications.

FIG. 38 is a schematic block diagram of an example module 260 thatincludes a power amplifier 252, a radio frequency switch 254, and aduplexer 241 that includes a raised frame bulk acoustic wave device inaccordance with one or more embodiments, and an antenna switch 242. Themodule 260 can include elements of the module 240 and elements of themodule 250.

One or more filters with any suitable number of raised frame bulkacoustic devices can be implemented in a variety of wirelesscommunication devices. FIG. 39Ais a schematic block diagram of anexample wireless communication device 270 that includes a filter 273with one or more raised frame bulk acoustic wave resonators inaccordance with any suitable principles and advantages disclosed herein.The wireless communication device 270 can be any suitable wirelesscommunication device. For instance, a wireless communication device 270can be a mobile phone, such as a smart phone. As illustrated, thewireless communication device 270 includes an antenna 271, a radiofrequency (RF) front end 272 that includes filter 273, an RF transceiver274, a processor 275, a memory 276, and a user interface 277. Theantenna 271 can transmit RF signals provided by the RF front end 272.The antenna 271 can provide received RF signals to the RF front end 272for processing.

The RF front end 272 can include one or more power amplifiers, one ormore low noise amplifiers, RF switches, receive filters, transmitfilters, duplex filters, filters of a multiplexer, filters of adiplexers or other frequency multiplexing circuit, or any suitablecombination thereof. The RF front end 272 can transmit and receive RFsignals associated with any suitable communication standards. Any of themulti-layer raised frame bulk acoustic wave resonators disclosed hereincan be implemented in filters 273 of the RF front end 272.

The RF transceiver 274 can provide RF signals to the RF front end 272for amplification and/or other processing. The RF transceiver 274 canalso process an RF signal provided by a low noise amplifier of the RFfront end 272. The RF transceiver 274 is in communication with theprocessor 275. The processor 275 can be a baseband processor. Theprocessor 275 can provide any suitable base band processing functionsfor the wireless communication device 270. The memory 276 can beaccessed by the processor 275. The memory 276 can store any suitabledata for the wireless communication device 270. The processor 275 isalso in communication with the user interface 277. The user interface277 can be any suitable user interface, such as a display.

FIG. 39B is a schematic diagram of a wireless communication device 280that includes filters 273 in a radio frequency front end 272 and secondfilters 283 in a diversity receive module 282. The wirelesscommunication device 280 is like the wireless communication device 270of FIG. 39A, except that the wireless communication device 280 alsoincludes diversity receive features. As illustrated in FIG. 39B, thewireless communication device 280 can include a diversity antenna 281, adiversity module 282 configured to process signals received by thediversity antenna 281 and including filters 283, and a transceiver 274in communication with both the radio frequency front end 272 and thediversity receive module 282. One or more of the second filters 283 caninclude a bulk acoustic wave resonator with a multi-layer raised framestructure in accordance with any suitable principles and advantagesdisclosed herein.

Bulk acoustic wave devices disclosed herein can be included in a filterand/or a multiplexer arranged to filter a radio frequency signal in afifth generation (5G) New Radio (NR) operating band within FrequencyRange 1 (FR1). FR1 can from 410 megahertz (MHz) to 7.125 gigahertz(GHz), for example, as specified in a current 5G NR specification. Afilter arranged to filter a radio frequency signal in a 5G NR FR1operating band can include one or more bulk acoustic wave resonators beimplemented in accordance with any suitable principles and advantagesdisclosed herein.

5G NR carrier aggregation specifications can present technicalchallenges. For example, 5G carrier aggregations can have widerbandwidth and/or channel spacing than fourth generation (4G) Long TermEvolution (LTE) carrier aggregations. Carrier aggregation bandwidth incertain 5G FR1 applications can be in a range from 120 MHz to 400 MHz,such as in a range from 120 MHz to 200 MHz. Carrier spacing in certain5G FR1 applications can be up to 100 MHz. Bulk acoustic wave resonatorswith a raised frame structure as disclosed herein can achieve lowinsertion loss and low Gamma loss, in some embodiments. The frequency ofa raised frame mode of such a bulk acoustic wave resonator can be movedsignificantly away from a resonant frequency of the bulk acoustic waveresonator. Accordingly, the raised frame mode can be outside of acarrier aggregation band even with the wider carrier aggregationbandwidth and/or channel spacing within FR1 in 5G specifications. Thiscan reduce and/or eliminate Gamma degradation in an operating band ofanother carrier of a carrier aggregation. In some instances, Gamma canbe increased in the operating band of the other carrier of the carrieraggregation.

Any of the embodiments described above can be implemented in associationwith mobile devices such as cellular handsets. The principles andadvantages of the embodiments can be used for any systems or apparatus,such as any uplink wireless communication device, that could benefitfrom any of the embodiments described herein. The teachings herein areapplicable to a variety of systems. Although this disclosure includessome example embodiments, the teachings described herein can be appliedto a variety of structures. Any of the principles and advantagesdiscussed herein can be implemented in association with RF circuitsconfigured to process signals in a frequency range from about 30 kHz to300 GHz, such as in a frequency range from about 450 MHz to 8.5 GHz.

Aspects of this disclosure can be implemented in various electronicdevices. Examples of the electronic devices can include, but are notlimited to, consumer electronic products, parts of the consumerelectronic products such as packaged radio frequency modules, uplinkwireless communication devices, wireless communication infrastructure,electronic test equipment, etc. Examples of the electronic devices caninclude, but are not limited to, a mobile phone such as a smart phone, awearable computing device such as a smart watch or an ear piece, atelephone, a television, a computer monitor, a computer, a modem, ahand-held computer, a laptop computer, a tablet computer, a microwave, arefrigerator, a vehicular electronics system such as an automotiveelectronics system, a stereo system, a digital music player, a radio, acamera such as a digital camera, a portable memory chip, a washer, adryer, a washer/dryer, a copier, a facsimile machine, a scanner, amulti-functional peripheral device, a wrist watch, a clock, etc.Further, the electronic devices can include unfinished products.

Unless the context indicates otherwise, throughout the description andthe claims, the words “comprise,” “comprising,” “include,” “including”and the like are to generally be construed in an inclusive sense, asopposed to an exclusive or exhaustive sense; that is to say, in thesense of “including, but not limited to.” Conditional language usedherein, such as, among others, “can,” “could,” “might,” “may,” “e.g.,”“for example,” “such as” and the like, unless specifically statedotherwise, or otherwise understood within the context as used, isgenerally intended to convey that certain embodiments include, whileother embodiments do not include, certain features, elements and/orstates. The word “coupled”, as generally used herein, refers to two ormore elements that may be either directly connected, or connected by wayof one or more intermediate elements. Likewise, the word “connected”, asgenerally used herein, refers to two or more elements that may be eitherdirectly connected, or connected by way of one or more intermediateelements. Additionally, the words “herein,” “above,” “below,” and wordsof similar import, when used in this application, shall refer to thisapplication as a whole and not to any particular portions of thisapplication. Where the context permits, words in the above DetailedDescription using the singular or plural number may also include theplural or singular number respectively.

While certain embodiments have been described, these embodiments havebeen presented by way of example only, and are not intended to limit thescope of the disclosure. Indeed, the novel resonators, devices, modules,apparatus, methods, and systems described herein may be embodied in avariety of other forms. Furthermore, various omissions, substitutionsand changes in the form of the resonators, devices, modules, apparatus,methods, and systems described herein may be made without departing fromthe spirit of the disclosure. For example, while blocks are presented ina given arrangement, alternative embodiments may perform similarfunctionalities with different components and/or circuit topologies, andsome blocks may be deleted, moved, added, subdivided, combined, and/ormodified. Each of these blocks may be implemented in a variety ofdifferent ways. Any suitable combination of the elements and/or acts ofthe various embodiments described above can be combined to providefurther embodiments. The accompanying claims and their equivalents areintended to cover such forms or modifications as would fall within thescope and spirit of the disclosure.

The following is claimed:
 1. A bulk acoustic wave device comprising: afirst electrode; a second electrode; a piezoelectric layer between thefirst electrode and the second electrode; and a raised frame structureincluding a first raised frame layer and a second raised frame layer,the second raised frame layer having a higher acoustic impedance thanthe first raised frame layer, the second raised frame layer overlappinga portion of the first raised frame layer, and the first raised framelayer extending further inward than the second raised frame layer. 2.The bulk acoustic wave device of claim 1, wherein the first raised framelayer extends further inward than the second raised frame layer by adistance that is between about 50% and about 100% of the combinedthickness of the first electrode, the piezoelectric layer, and thesecond electrode.
 3. The bulk acoustic wave device of claim 1, whereinthe first raised frame layer includes a non-gradient portion with asubstantially uniform thickness and a gradient portion with a taperedthickness, and the non-gradient portion of the first raised frame layerextends further inward than the second raised frame layer.
 4. The bulkacoustic wave device of claim 1, wherein the first raised frame layerincludes a non-gradient portion with a substantially uniform thicknessand a gradient portion with a tapered thickness, and the non-gradientportion of the first raised frame layer has a width that is larger thana combined thickness of the first electrode, the piezoelectric layer,and the second electrode.
 5. The bulk acoustic wave device of claim 4,wherein the non-gradient portion of the first raised frame layer isbetween about 1.5 and about 2.5 times larger than the combined thicknessof the first electrode, the piezoelectric layer, and the secondelectrode.
 6. The bulk acoustic wave device of claim 1, wherein thefirst raised frame layer includes a non-gradient portion with asubstantially uniform thickness and a gradient portion with a taperedthickness, the second raised frame layer includes a non-gradient portionwith a substantially uniform thickness and a gradient portion with atapered thickness, and the non-gradient portion of the first raisedframe layer is wider than the non-gradient portion of the second raisedframe layer.
 7. The bulk acoustic wave device of claim 6, whereinnon-gradient portion of the first raised frame layer is about 2 times toabout 8 times wider than the non-gradient portion of the second raisedframe layer.
 8. The bulk acoustic wave device of claim 1, wherein thefirst raised frame layer includes a non-gradient portion with asubstantially uniform thickness and a gradient portion with a taperedthickness, the second raised frame layer includes a non-gradient portionwith a substantially uniform thickness and a gradient portion with atapered thickness, and the non-gradient portion of the first raisedframe layer extends further inward than the gradient portion of thesecond raised frame layer by a distance that is between about 25% andabout 75% of the combined thickness of the first electrode, thepiezoelectric layer, and the second electrode.
 9. The bulk acoustic wavedevice of claim 1, wherein the first raised frame layer has a thicknessbetween about 0.02 to about 0.4 times the combined thickness of thefirst electrode, the piezoelectric layer, and the second electrode. 10.The bulk acoustic wave device of any claim 1, wherein the second raisedframe layer has a thickness between about 0.02 to about 0.4 times thecombined thickness of the first electrode, the piezoelectric layer, andthe second electrode.
 11. The bulk acoustic wave device claim 1,comprising an active region where the first electrode overlaps thesecond electrode, the active region including a middle area, and theraised frame structure positioned outside the middle area of the activeregion, the combined thickness of the first electrode, the piezoelectriclayer, and the second electrode being taken at the middle area of theactive region.
 12. The bulk acoustic wave device of claim 1, wherein thefirst raised frame layer is between the first electrode and the secondelectrode, the piezoelectric layer is over the first electrode, thesecond electrode is over the piezoelectric layer, and the first raisedframe layer is between the second electrode and the piezoelectric layer.13. The bulk acoustic wave device of claim 12, wherein the second raisedframe layer is over the second electrode.
 14. The bulk acoustic wavedevice of claim 1, wherein the first raised frame layer is between thefirst electrode and the second electrode, the piezoelectric layer isover the first electrode, the second electrode is over the piezoelectriclayer, and the first raised frame layer is between the first electrodeand the piezoelectric layer.
 15. The bulk acoustic wave device of claim14, wherein the second raised frame layer is over the second electrode.16. A bulk acoustic wave device comprising: a first electrode; a secondelectrode; a piezoelectric layer between the first electrode and thesecond electrode; and a raised frame structure that includes a raisedframe layer having a lower acoustic impedance than at least one of thefirst electrode, the second electrode, and the piezoelectric layer, anda width of the raised frame layer that overlaps the first and secondelectrodes is between about 1.5 times to about 4 times larger than thecombined thickness of the first electrode, the piezoelectric layer, andthe second electrode.
 17. The bulk acoustic wave device of claim 16,wherein the width of the raised frame layer that overlaps the first andsecond electrodes is between about 2 times to about 3 times wider thanthe combined thickness of the first electrode, the piezoelectric layer,and the second electrode.
 18. The bulk acoustic wave device of claim 16,wherein the raised frame layer includes a non-gradient portion with asubstantially uniform thickness and a gradient portion with a taperedthickness, and the non-gradient portion of the raised frame layer has awidth that is larger than a combined thickness of the first electrode,the piezoelectric layer, and the second electrode.
 19. The bulk acousticwave device of claim 18, wherein the non-gradient portion of the raisedframe layer is between about 1.5 and about 2.5 times larger than thecombined thickness of the first electrode, the piezoelectric layer, andthe second electrode.
 20. The bulk acoustic wave device of claim 16,wherein the raised frame layer has a thickness between about 0.02 toabout 0.4 times the combined thickness of the first electrode, thepiezoelectric layer, and the second electrode.
 21. The bulk acousticwave device of claim 16, wherein the raised frame layer has a thicknessbetween about 0.06 to about 0.15 times the combined thickness of thefirst electrode, the piezoelectric layer, and the second electrode. 22.The bulk acoustic wave device of claim 16, wherein the raised framelayer is between the first electrode and the second electrode, thepiezoelectric layer is over the first electrode, the second electrode isover the piezoelectric layer, and the raised frame layer is between thesecond electrode and the piezoelectric layer.
 23. The bulk acoustic wavedevice of claim 16, wherein the raised frame layer is between the firstelectrode and the second electrode, the piezoelectric layer is over thefirst electrode, the second electrode is over the piezoelectric layer,and the raised frame layer is between the first electrode and thepiezoelectric layer.
 24. The bulk acoustic wave device of claim 16,further comprising an additional raised frame layer that has higheracoustic impedance than the raised frame layer.